# Carrier 58MVP Blower Problem



## mickd

Kicked on the A/C today. Noticed when I got home the house wasn't cool and no air flow coming from the vents. Came down to check the furnace. Yep Frozen! My first thought was filter or low freon. The furnace is flashing a code in amber. 4 short and 1 long flash. Book indicates blower motor fault. Any ideas? Thank for the help


----------



## MaxPierre

*Me too!*

I seem to be having a similar problem. I got codes "44" and "41". When I get both, I'm instructed to check the wiring to the blower. The HVAC tech tells me that the blower is blown (pun intended) and it will need to be replaced.

I also followed the suggestions as if I got each code individually. In this case I was instructed to make sure the registers was opened (which are all open now as opposed to only a few being open). I was also told to check the filter... I did, and though dirty it didn't seem to be the problem.

So, I'm in a similar boat... any other suggestions other than replacing the blower?


----------



## Summit Heating & Air

Max, if your filter was dirty it may have caused a problem. Turn your furnace switch off then on now that you've changed the filter. If it does not start you'll need to call a service tech.


----------



## Mike Swearingen

I am not an HVAC tech, just a long-time DIYer. I rarely touch anything to do with our HVAC.
However, we had a 4-ton Carrier heatpump installed in 1998 to replace an Amana. The Carrier unit has had constant problems with the *blower motor control module* that attaches under it, not the blower motor itself. (Supposedly a Carrier engineering/design problem.) 
I average replacing the control module about every 1-2 years. It has happened so frequently that I keep a spare module on hand, and change it out myself. (They cost about $200 =/-).
This is the first and last Carrier that I will ever have.
Your problem is probably the control module.
Mike


----------



## #CARRIERMAN

Hi mickd & all

A little information to help all of you with your current and potentially future problems. The blower motor that this furnace use is a D/C motor with an A/C pulse modulator on the back of it. With that being said, this particular design motors job is to deliver a constant CFM supply for the duct system. If you are using a high merve rated filter, this could be a potential cause for the motor module failure. But the most common cause is poor duct design. As I said earlier, this motor will continue to speed up to generate the required CFM. In doing so it also raises the statc pressure on the duct and causes excessive amperage on the motor and controller. This is what causes the majority of the contoller failure. The biggest problem when people retrofit with this beautiful piece of equipment is they never look at the duct to see if it can be used. This particular furnace is a God send for the consumer if the installing company is a knowledgeable one. The most common response you will get from the majority of installing companys is that there is nothing wrong with the duct work, it is the furnace. I have personally installed a great many of these over the years, including the one in my own house. The longest running one I have to date was installed almost 11 years ago with no mechanical failure period! The one in my own house has been here for almost 9 years its self. I cannot stress enough that when selecting a filter, by all means use a pleated filter. There is nothing better in a disposable filter for cleaning and air delivery. But please listen when I say not to use the ones that have the paper looking media. Use the filters with the soft polyester media and change them monthly. But above all, have your duct work calculated for .50 static pressure max including filter. If your HVAC man becomes defensive about your duct problem, find one that is a professional and is willing to fix the problem, not just C/O an expensive control module every year or so.

Good luck
Rusty


----------



## bob reynolds

*High Efficiency Blower motors common problem*

These high efficiency variable speed blower motors are maufactured by GE. They are used in many brands including Lennox, Carrier, Bryant, Payne, York and Trane. 

There are two parts to the blower motor. 

The two parts are the motor itself and the ECM module that is attached to the blower motor. The ECM looks like a black hubcab and it is attached, to the motor, with two long bolts.

You can remove the ECM module by simply unscrewing the two long bolts. You do not have to remove the blower motor from the mounting.

The motors in different series and brands are often the same. The difference is the ECM module. The ECM module must be matched up exactly or it will not work.

What usually fails on these high efficiency units is the ECM module. A service truck can not possibly carry all of the hundreds of ECM modules that are used in the various brands and series of brands.

However, the part that often fails in the ECM unit is part number SG379 which is a black disc about the size of a quarter in the center of the ECM. 

You can look at the SG379 disk and often tell it has failed without any further checking. The disk will often be broken, brittle or disconnected from the circuit board, and there will be an obvious spot on the circuit board that has received a lot of heat. As long as the board is not broken, or deformed and the traces are in place, then this componet can be replaced. This component is designed to take a lot of heat and the circuit board will be discolored from the heat. This is normal and this is common.

This propierity part is a thermistor and it is used for surge protection as well as regulating the current to the motor. 

SG379 has a finite life and like a light bulb it gets weaker and weaker until it finally just fails. 

Although not available from GE or any or the HVAC companies, a SG379 part substitute, manufactured to OEM standards, is available from amazingkeys.com and can be soldered into the ECM circuit board in about 5 minutes. 

If you are a serviceman, you can keep a few of these parts on your service truck and have the unit up and running in one service call and not have to replace the motor or the ECM. This also saves the customer a $1500 blower motor replacement or an ECM replacement.


----------



## MrShadetree0222

Wow i wish i could of gotten help like this with all my problems! wow this is some of the best information i hav eyet to of read coming form a Professional for a Diy'er! Thanks guys fo rthe great info, though not of use fo rme, this is some great info for the users of the compatible system in discussion!


----------



## keith20mm

There's something else you need to know about the ECM, that has to do with the controller section of the motor. In the earlier design, when the controller is connected, there are three sliding copper contacts that are pins that go into mating holes in the circuit board. The problem here is that this is not a 'gas tight' connection.. air can get into the contact surface, and with it, moisture... and eventually there will form corrosion and the contacts will burn up from resistance accumulation. The newer ECM have a real connector here, male and female, in a solid locking plastic housing. The contacts in the newer units make very good contact and the plastic housing hold the contacts firmly. 

So when you look into the mate up of the circuit board in the ECMs, look specifically for this lame, open, copper pin tri-connector, and plan on that failing from vibration/corrosion, maybe look to replace it either with solid wire soldered in, or some 'good' repair technique.

As to the pointer on the thermistor device, THANKS!!! I'll be able to repair my old motor with that info, and I'll also replace the lame tri-connector.

These motors are HELLACIOUSLY expensive.


----------



## denhunter

AND expensive for no good reason. Carrier will not allow the dealers to get them repaired, because they want you to dump the 700 for a new mod and motor. 

There is a point where the claims of efficiency are outweighed by the cost of repair. And with Carrier/GE motors and mods, that point was long ago met. They ought to be ashamed of themselves. This is a relatively simple unit (compared to you common home computer, or kid's video game), but the prices on them keep getting higher.

I understand that GE sold off the portion of the company that makes them. Hope springs eternal. It seems stupid that the cost of the motor and mod are one half the cost of a whole new blower unit on Ebay.


----------



## David 321

*58MVP Carrier Blower*

I followed the leads and guides and was able to replace the damaged thermister for only a few bucks, but with no good results.
I received the replacement ECM ($259) for my exact motor on the second workday. Shipping was free and my blower was up and operational in one hour. This sure saved me from an alternative of replacing my furnace- as I would have considered before spending a thousand for someone else to fix or hundreds invested to be told they need to replace with a new unit anyway! I sure am glad that there was someone willing to address a problem that Carrier doesn't want to deal with. I'm amazed that they designed the expensive ECM to act as a replacement for a five cent fuse. I'll go back to PSC motors for my next furnaces, at least they are more of a fix it yourself.


----------



## beenthere

Carrier tends to always use the newest version of the ECM motor. So they generally have the most expensive one you can get.

The early motors(all ECMs) didn't have speed limiting programing. And the modules don't hold up well to running the motor at full or near full speeds all the time.


----------



## yuri

Yah, can you imagine what a plugged air filter must do to the speed and life of them. I had one try and collapse the ductwork it was so plugged and cavitating. People spend $4-6000 on a furnace and give you the deer in the headlight look when you tell them to spend $95 a yr on maintenance.:no:
Reminds me of Red Foxx aka Fred Sanford, `My heart, my heart:laughing:


----------



## beenthere

Ya.

And then so many of them are installed to get "more" air to what ever rooms. On undersized ducts, and end up running at statics above 1.2". No wonder they burn out.


----------



## ossicles1

This and other posts with this information has been such a great help....I went from a quote to replace blower moter for 1300.00 to replacing the thermistor (SL22) for 1.68 and about 45 minutes of time (blower motor was just fine) So far, the furnace has worked great! Thanks to all of you for posting this information




bob reynolds said:


> These high efficiency variable speed blower motors are maufactured by GE. They are used in many brands including Lennox, Carrier, Bryant, Payne, York and Trane.
> 
> There are two parts to the blower motor.
> 
> The two parts are the motor itself and the ECM module that is attached to the blower motor. The ECM looks like a black hubcab and it is attached, to the motor, with two long bolts.
> 
> You can remove the ECM module by simply unscrewing the two long bolts. You do not have to remove the blower motor from the mounting.
> 
> The motors in different series and brands are often the same. The difference is the ECM module. The ECM module must be matched up exactly or it will not work.
> 
> What usually fails on these high efficiency units is the ECM module. A service truck can not possibly carry all of the hundreds of ECM modules that are used in the various brands and series of brands.
> 
> However, the part that often fails in the ECM unit is part number SG379 which is a black disc about the size of a quarter in the center of the ECM.
> 
> You can look at the SG379 disk and often tell it has failed without any further checking. The disk will often be broken, brittle or disconnected from the circuit board, and there will be an obvious spot on the circuit board that has received a lot of heat. As long as the board is not broken, or deformed and the traces are in place, then this componet can be replaced. This component is designed to take a lot of heat and the circuit board will be discolored from the heat. This is normal and this is common.
> 
> This propierity part is a thermistor and it is used for surge protection as well as regulating the current to the motor.
> 
> SG379 has a finite life and like a light bulb it gets weaker and weaker until it finally just fails.
> 
> Although not available from GE or any or the HVAC companies, a SG379 part substitute, manufactured to OEM standards, is available from amazingkeys.com and can be soldered into the ECM circuit board in about 5 minutes.
> 
> If you are a serviceman, you can keep a few of these parts on your service truck and have the unit up and running in one service call and not have to replace the motor or the ECM. This also saves the customer a $1500 blower motor replacement or an ECM replacement.


----------



## ahenderson

GE+5sme39sL0005 Motor
OK There are 100s of posts about Carrier, trane and others with motor problem that can be fixed with a new thermister. Done that, replaced the themister. Have 2 motors both have the same problem .
Motor GE 5SME39-------The family of motors used on these Hi End furnaces
The problem 
I cleared out the old fault codes in the ECM. It had 41 of course (blower outside valid speed range) 
Hooked the motor up, Turn on the system and it starts through the runup process with enducer motor kicking on ect. 
When it gets to the point where the computer tells it to Run the variable speed motor to test it I get a pulse that jerks the motor but it does not start and run. Then it shows Fault 44 (blower calibration fault).
I dont find this problem anywhere on the net. I dont think it is in the motor or the controller attached too the motor. Have 2 motors Replaced the thermister in one and hotwired around it in the other one. 
This furnace had a problem for a while that it would stop working. If you turned the power off and back on a couple of times it would start and work for weeks or months. 
This thing has a huge 12ADC Transformer on it, Weighs a couple of pounds. Could it be the transformer? How do you check one of these I get 120 volts to it but no voltage (I checked for 12) out of it. I suspect maybe the transformer only puts out voltage when it is gets loaded by the motor controller. 
Guys Can you give me some things to check. Is there another component in the Motor Controller that is causing this problem (30 vilt thermister replaced with a new one). Point me to another place on the web that might help. Thanks


----------



## beenthere

Sounds more like you have an air flow problem that needs to be corrected. Or your just going to keep burning out controllers.


----------



## hvaclover

beenthere said:


> Sounds more like you have an air flow problem that needs to be corrected. Or your just going to keep burning out controllers.


Than wouldn't only the resistor burn out?


----------



## beenthere

hvaclover said:


> Than wouldn't only the resistor burn out?


More then the resistor can burn out because of low air flow. Just generally the resistor goes before anything else. but not always.

Also depends on how bad the air flow is.


----------



## yeshoney

bob reynolds said:


> These high efficiency variable speed blower motors are maufactured by GE. They are used in many brands including Lennox, Carrier, Bryant, Payne, York and Trane.
> 
> There are two parts to the blower motor.
> 
> The two parts are the motor itself and the ECM module that is attached to the blower motor. The ECM looks like a black hubcab and it is attached, to the motor, with two long bolts.
> 
> You can remove the ECM module by simply unscrewing the two long bolts. You do not have to remove the blower motor from the mounting.
> 
> The motors in different series and brands are often the same. The difference is the ECM module. The ECM module must be matched up exactly or it will not work.
> 
> What usually fails on these high efficiency units is the ECM module. A service truck can not possibly carry all of the hundreds of ECM modules that are used in the various brands and series of brands.
> 
> However, the part that often fails in the ECM unit is part number SG379 which is a black disc about the size of a quarter in the center of the ECM.
> 
> You can look at the SG379 disk and often tell it has failed without any further checking. The disk will often be broken, brittle or disconnected from the circuit board, and there will be an obvious spot on the circuit board that has received a lot of heat. As long as the board is not broken, or deformed and the traces are in place, then this componet can be replaced. This component is designed to take a lot of heat and the circuit board will be discolored from the heat. This is normal and this is common.
> 
> This propierity part is a thermistor and it is used for surge protection as well as regulating the current to the motor.
> 
> SG379 has a finite life and like a light bulb it gets weaker and weaker until it finally just fails.
> 
> Although not available from GE or any or the HVAC companies, a SG379 part substitute, manufactured to OEM standards, is available from amazingkeys.com and can be soldered into the ECM circuit board in about 5 minutes.
> 
> If you are a serviceman, you can keep a few of these parts on your service truck and have the unit up and running in one service call and not have to replace the motor or the ECM. This also saves the customer a $1500 blower motor replacement or an ECM replacement.


 
Bob, thanks. Your info saved me well over $1000 dollars. After a lightening storm and a power outage our Carrier 58MVP furnace would'nt start. I checked for power to the unit and it was good. I set the diagnostics switch and ran the tests. I got the 44 and 41 LED codes no matter what I did. I was about to buy a new control module (around $200) and then a new motor ($800) if necessary. However, I came acrosss the info you provided and opened the control module, looked at the black disk and found it had burned out. A little more research and I learned it was an _SG 348 Thermistor. _I ordered one from Amazingkeys.com for $20.00 (only place I could find it on the internet). After replacing it everything works fine. You the man! :thumbsup:


----------



## hvaclover

yeshoney said:


> Bob, thanks. Your info saved me well over $1000 dollars. After a lightening storm and a power outage our Carrier 58MVP furnace would'nt start. I checked for power to the unit and it was good. I set the diagnostics switch and ran the tests. I got the 44 and 41 LED codes no matter what I did. I was about to buy a new control module (around $200) and then a new motor ($800) if necessary. However, I came acrosss the info you provided and opened the control module, looked at the black disk and found it had burned out. A little more research and I learned it was an _SG 348 Thermistor. _I ordered one from Amazingkeys.com for $20.00 (only place I could find it on the internet). After replacing it everything works fine. You the man! :thumbsup:


Did you bother to check the tolerance on the thermistor? There ar plenty of generic replacements around but they are off spec by as much as 4%.
Know what that will do to the windings?

See you in about a year with a bad thermistor and motor.


----------



## yeshoney

Hvaclover, thanks for the heads-up. I'm not savvy enough to check tolerance on a thermistor :huh:. Can you guide me or point me to info. Also, what will it do to the windings?

thanks.


----------



## hvaclover

yeshoney said:


> Hvaclover, thanks for the heads-up. I'm not savvy enough to check tolerance on a thermistor :huh:. Can you guide me or point me to info. Also, what will it do to the windings?
> 
> thanks.


The thermistors are over heat protection for the motor and module.. GE uses very close tolerances on these thermistors. Since China has gotten into the solid state component business we have have been seeing a lot of off spec tolerance
pieces flooding the market from even reputable suppliers.

The thermistors from GE suppliers have a .1 variance. But the knock offs are off by 3-4%. Could make the difference between a motor surviving an over heat condition and burning up.


----------



## redwalsh

*Re Bob Reynold's SG379 Part replacement fix above*

Excellent Post Bob Reynolds! Very clear. Thank you. 

I am not very experienced at soldering - never soldered on a circuit board - but will give this a try. The problem is one of the thin wire legs of the thermasister snapped right at the bottom where it connects into the board. Any suggestion on how to solder the new one on? Alternatively, any suggestion on someone who might be a regular circuit board repair person that I could take this to say a TV repair shop? 

btw, the S379 is now $19.99 at amazingkeys.com. Any one find a cheaper source? Would like to get a couple as we have 2 units as this is the second time one of the modules has gone bad. Both units were purchased/installed in 2001. One went out in August 2010, the other in January, 2011. Clearly a design flaw if this one little part is so weak and not easily replaced by plugin Carrier part. Carrier should be embarrassed.


----------



## hvaclover

redwalsh said:


> Excellent Post Bob Reynolds! Very clear. Thank you.
> 
> I am not very experienced at soldering - never soldered on a circuit board - but will give this a try. The problem is one of the thin wire legs of the thermasister snapped right at the bottom where it connects into the board. Any suggestion on how to solder the new one on? Alternatively, any suggestion on someone who might be a regular circuit board repair person that I could take this to say a TV repair shop?
> 
> btw, the S379 is now $19.99 at amazingkeys.com. Any one find a cheaper source? Would like to get a couple as we have 2 units as this is the second time one of the modules has gone bad. Both units were purchased/installed in 2001. One went out in August 2010, the other in January, 2011. Clearly a design flaw if this one little part is so weak and not easily replaced by plugin Carrier part. Carrier should be embarrassed.


 
Carrier should be embarrassed? Why? There are all kinds of reasons your part blew that have nothing to do with the quality of the part.

I have already pointed out that repairing in other posts that Homeowner repair of the motor would void your home insurance if a fire ever occurred. And the blower does not have to be the cause of the fire to void the home owners insurance.

Bob Reynolds makes it sound so easy...

ButI don't see where Bob Reynolds pointed out the chance of extreme injury or death when opening the motor. There are very powerful capacitors he didn't mention that will discharge a dangerous intensity of voltage.

This ECM motor module is not a passive electronic product like a computer or a stereo system. 
The ECM module is exposed to the vibrations, surges, over heat of a plugged air filter, ruinously low air flow thru overly restrictive AC coils, over working of the ECM against duct work that is tool small for the ECM to work against.

If you think your hand soldered resistor is going to remain intact against that kind of punishment then go for it.

There is a reason the boards are machine soldered. You get a consistent line of quality and durability much better than hand soldering can deliver. 

Just curious, how long have you had this equipment with the defective ECM?


----------



## adamabcd

Bob, let me add my thanks for your posting. I followed your advice, replaced the thermistor, and now my furnace is working fine again! In my case, I had to dismount the blower motor assembly from the chassis of the furnace to get the ecm off - there wasn't clearance to remove it otherwise - but this was not very difficult. When I looked at the old thermistor, I didn't see any signs of a problem. There was no cracking, discoloration, or anything like that. But since I had already taken it apart and procured the replacement part (I confirm it now costs $19.99) I figured I'd try it anyway, and sure enough it solved the problem.

In answer to some of hvaclover's concerns, I agree that if you have never soldered any components on a circuit board before this may not be the place you want to start. But for the potential saving of $20 vs. $1000 for a repair it may be worth rounding up a friend who has.


----------



## cbandera

*Thermistor*

Thanks to everyone who posted info on this site and saving me over a grand (another 58mvp with a blown SG379). It is you - not Larry Page from Google or Mark Zuckerberg from Facebook - that make the web valuable.

My contribution to the cause:

1. If you are getting error code 41 (Blower Motor Fault), first follow the diagnostics procedure in the installation manual: verify that the harness to the ECM carries 115Vac (black wires), 12Vdc (red and green wires), and 5Vdc (yellow and green wires). If so, then the problem may very well be the thermistor.

2. The heat that blows the thermistor can also damage the trace on the ECM circuit board (the metal foil underneath the board, to which the thermistor leads are soldered). In my case, the foil was starting to peel off the board. Be careful unsoldering/removing the old thermistor, and instering/soldering the new one. When you insert the new thermistor, make sure you don't tear the foil from the circuit board in the process. Instead of clipping off the excess lead length, I ran each lead in parallel with its corresponding trace, soldering it at component points along the way. This structurally reinforces the trace, and improves heat dissipation.

3. AmazingKeys is great. My blower blew Thursday night, and thanks to this forum I traced it to the thermistor in 30 minutes. Ordered the SG379 from AmazingKeys at 11:30pm, with the message that they notify me if the part was NOT in stock. Joe Friday (anyone on this forum remember the TV show?) from AmazingKeys called me moments later to confirm that they had them in stock, and to offer sending it to me via USPS which has saturday delivery. By noon on Saturday, the family was once again enjoying some nice A/C.


----------



## ColoradoDave

I had the dreaded 44 / 41 blower problem on my 58MVP with the motor not spinning after the filter clogged too much..
I took off the ECM and the Thermistor was open, so I ordered one from Amazing Keys and replaced it. The Lands were fine.
Motor now spins, doesn't make any noise except a slight growl when starting up, and still gets 44 / 41. There is also a very slight tick when running. The blower wheel also has about 1/8" variance side-to-side out of center ( Like wiggling back and forth )
I removed the Blower Assembly and inspected the motor. It spins freely and has no noticeable play in the shaft bearings.
When I had it out and separated from the blower wheel, I plugged it in and it ramped up and down several times from low speed to high speed then got the error codes. It was very smooth with no tick noise or other noises.
I'm thinking that something else in the ecm was damaged, but hate to spend the $ for an ECM if it could be the motor.
Also, Is there a way to jumper around the speed detection circuitry to get the A/C back up in the meantime ?


----------



## beenthere

Ticking noise would most likely be the motor. Could be a magnet coming loose.


----------



## ColoradoDave

So, I put the whole thing back together and it came up on fan fine. I then turned it off, put the cover back on and switched it on Cool and it's working now. I'm not sure for how long, though. The ticking noise appears to have gone also. Maybe it was a magnet in the motor and moving it around relocated it back to its' proper place. If it fails again and the ticking returns also, that will be incriminating on the motor, I guess.

One question I have, though, is ;

Is the blower speed error determined by the ECM on the motor and reported back to the main board, or does the ECM on the motor merely report back the speed and the main board determines if that is an error or not ?


----------



## yuri

As far as I know there is programming built into the motor module and circuit board so they work/talk together. The latest generation of ECM motors all the programming is in the main circuit board and the motors are somewhat generic now.


----------



## ACfromCa

*ColoradoDave, same wiggling thing happened to my unit,*



ColoradoDave said:


> I had the dreaded 44 / 41 blower problem on my 58MVP with the motor not spinning after the filter clogged too much..
> Also, Is there a way to jumper around the speed detection circuitry to get the A/C back up in the meantime ?


 
Dave, I had simillar problem without trimister change, where motor wiggles up & back words few times. AC compressor is working fine & freezup the lines but the blower motor is not coming on.
I had spare another blower motor never used on craigslist I had bought. So I hooked up that, this one did the same wiggling. Now while I went to turn off the thermostat it had a small short noice, I came back to see it all I can smell is little smell but nothing else. 
I did open the old blower motor ECM and transmister is in good condition doesnt look burned. 
Any luck on your problem come back, I called tech spend an hr, called carrier, he was told motor or ECM, so I am still hanging on for a life saver. This unit was only used 2 years. My Carrier Air handler Model no is FK4CNB006 motor is 3/4hp


----------



## JJboy

You can do this test.

http://img824.imageshack.us/img824/5958/modulej.jpg


----------



## No Cones

Armed with a *SL22* and a sodering iron I have beet back the Money Demons!
Thank you all who have tirelessly given and given information, great photos, and even Videos to help people.

My Carrier unit is blowing ounce again!


----------



## JJboy

:thumbsup::thumbsup::thumbsup::thumbsup:


----------



## tamaswing

bob reynolds said:


> These high efficiency variable speed blower motors are maufactured by GE. They are used in many brands including Lennox, Carrier, Bryant, Payne, York and Trane.
> 
> There are two parts to the blower motor.
> 
> The two parts are the motor itself and the ECM module that is attached to the blower motor. The ECM looks like a black hubcab and it is attached, to the motor, with two long bolts.
> 
> You can remove the ECM module by simply unscrewing the two long bolts. You do not have to remove the blower motor from the mounting.
> 
> The motors in different series and brands are often the same. The difference is the ECM module. The ECM module must be matched up exactly or it will not work.
> 
> What usually fails on these high efficiency units is the ECM module. A service truck can not possibly carry all of the hundreds of ECM modules that are used in the various brands and series of brands.
> 
> However, the part that often fails in the ECM unit is part number SG379 which is a black disc about the size of a quarter in the center of the ECM.
> 
> You can look at the SG379 disk and often tell it has failed without any further checking. The disk will often be broken, brittle or disconnected from the circuit board, and there will be an obvious spot on the circuit board that has received a lot of heat. As long as the board is not broken, or deformed and the traces are in place, then this componet can be replaced. This component is designed to take a lot of heat and the circuit board will be discolored from the heat. This is normal and this is common.
> 
> This propierity part is a thermistor and it is used for surge protection as well as regulating the current to the motor.
> 
> SG379 has a finite life and like a light bulb it gets weaker and weaker until it finally just fails.
> 
> Although not available from GE or any or the HVAC companies, a SG379 part substitute, manufactured to OEM standards, is available from amazingkeys.com and can be soldered into the ECM circuit board in about 5 minutes.
> 
> If you are a serviceman, you can keep a few of these parts on your service truck and have the unit up and running in one service call and not have to replace the motor or the ECM. This also saves the customer a $1500 blower motor replacement or an ECM replacement.


I took off my ECM module and everything looked fine. Now what?


----------



## punchycool

Thx Bob Reynolds! I am in the middle of my thermistor repair, but have definitively found my issue. See this thread, posts 25 and 26....I'll update that thread mid week...including pictures. 

http://www.diychatroom.com/f17/variable-speed-trane-blower-motor-117160/index2/#post1092705


----------



## Indyxc

My ECM module on my Carrier 58 MVP took a dump today as well.

Unfortunately I was under the gun, and didn't want to start guessing so I called my Local HVAC guy, since my furance is in the attic, and hard to work on.

Between him and I we were able to pull the blower ASM in about an 1.5 hours, pulled the ECM module, saw the burnt disc. Luckily he had the module at his shop close by. Swapped it in and back up in running.

If it hadn't been 58 in the house already, and 14F outside, I would of gone the DIY route. 

Oh well, next time! Good thread.


----------



## punchycool

Indeed the thermistor replacement fixed me up! I'll try to get pictures up as well later. First attempt didn't get enough solder to wick through the thermistor to the other side. Unit went out 48 hrs later because of poor connection. 

I found I could pull the motor module out with it all mounted in just 2 min. Resoldered another new thermistor in and good to go since.


----------



## Mydogezra13

*Need help finding a SG349 thermistor*

I have a carrier model 58mvp. The blower stopped working and I did a code check and got codes 41 & 44. After looking at some chats here I seen that it could be the thermistor. I have removed the blower and the motor
(GE CB02 09Cb ) no other makings on the motor. I looked at the thermistor and it is burned.

Here is where I am running into trouble I have a model SG349 and can not find a replacement, been looking on line for 2 hours.

is the a similar one that can be used?

I may not be correct on this but I think mine is 1 OHM/ 30 Amp but not 100% sure.

Any and all help to get this fixed will be greatly appreciated. It is suppose to get hot again middle of next week. I can take the heat more worried for my special needs dogs.

Thanks

Mark


----------



## beenthere

http://www.amazingkeys.com/product/sg379-sg-379-thermistor-oem

http://www.sears.com/amazing-keys-i...istor-oem/p-SPM2146515803P?PDP_REDIRECT=false


----------



## Mydogezra13

beenthere said:


> http://www.amazingkeys.com/product/sg379-sg-379-thermistor-oem
> 
> http://www.sears.com/amazing-keys-i...istor-oem/p-SPM2146515803P?PDP_REDIRECT=false




Thanks!!!!!!!


----------



## Nando779

I wanted to find out if the issue I am having is related to the thermistor. I am under the impression the blower would not fire up at all if the thermistor or ECU were the issue? 

The symptons I am having are every now and then with no rhyme or reason, my blower will not fire up when the thermostat calls for it to. The outside unit will be running but no air is being blow out the vents. I will reset the unit in the attic by pulling the breaker and popping it back in and that will usually get it going (sometimes takes a few tries). Any idea?


----------



## beenthere

That would not be a thermistor problem. Look for the error code.


----------



## bskins47

*Module , Motor ????*

Okay I am at a loss ! I'm a tech but not a AC Tech so I get most of this info given - I have tried everything under the sun listed for this problem and still hitting a wall for a fix ! My air conditioner was working fine and all of the sudden the I heard a loud pop near the filter grill ,when I checked the filter it was bent from where it was sucked in - and it was completely full and and needed changing in a bad way - I'm guessing the popping noise was the filter because like I sad it was bent inward on the corner when I opened the door --- I the air unit outside runs and the inside runs and even putting out cold air ---- its just not cooling the house ---- No Ice --- No clogging ---- no water or dew anywhere ---- the module looks perfect (looks new) with no black marks and its not brittle looking like other threads to look for --- I metered the resistor and it has 1 OHM --- I checked power to motor and I got power going to motor - I also cleaned coils and checked the safety switch , I confirmed the thermostat works --- everything pans out A OKAY - Im at a lost of why it wont blow the cold air its producing ?? Any help is very much appreciated - thanks in advance!!!


----------



## beenthere

Could be the control board is not communicating with the motor.


----------



## bskins47

is there a way to reset the control board ?? 
I appreciate your help..... Thank you again!


----------



## Bitters

Turn the furnace breaker off and on.


----------



## bskins47

I have turned the main breaker off to the unit multiple times ---- is there another breaker ???? thank you


----------



## FurnaceFellow

*Cheap Thermistor for Carrier 58MVP-120 ECM*

This forum saved me $1500! Thanks.


----------



## kolcun

Hi all,

I thought I'd add my scenario to the forum in case it might help others.

I ran into the same blower-not-working issue that seems common with this motor/ecm. 

I was hoping my issue would be the common thermistor problem, and after a quick fix I'd be on my way. Unfortunately this wasn't the case for me, and I ended up with a full replacement of the module and motor.

I followed the troubleshooting flow chart in the furnace manual, and all the voltages on the motor connectors, and furnace control board were correct.

I took apart the motor, hoping to find the burnt out thermistor, and had a very hard time disconnecting the 3 pin motor connector from the control module. Finally I got it apart and noticed it was all burnt out - in fact one of the pins had broken out of the control module.

It seems something different happened to mine, and it was just toast. I replaced both the ECM and the motor - at a cost of $720 Canadian (just outside of Toronto). The bulk of the cost was the ECM.

See some pictures here - imgur.com/a/x2BzY

Thanks for all the discussion - it really helped.


----------



## jricharc

I have a Trane TWE037E13FB1 air handler and I woke up to no heat yesterday. I checked the fuse and that was good it's getting power but the fan won't kick on, it was doing the jumping back and forth. I spun it with my hand and it started and ran for about 5min. before turning off again. Here are a few pictures of the ECM I pulled off the blower motor. I read that the thermistor goes bad but this one seems to look fine? Any other thoughts?


----------



## DOUG1111

Some do not look bad but are bad- can not go by looks all the time . read all the post above good info. If you need to replace mtr think about going with a PSC mtr with new capacitor & a relay or contactor.


----------



## mbnicholson

I have a 58MVP100 and the Motor Controller had a failed thermistor (black disk on controller). I ordered an "OEM" replacement from Repairclinic part number HK44ER158. It was NOT a GE be rather a Genteq. It had a standoff collar to make it fit and installed and connected just fine. But I am still getting the 4 short blinks and 1 long blink status light. Indicating a failed blower motor. When shorting our the thermistor on the old unit it works. Any insight is appreciated.


----------



## user_12345a

The motor's module must have the correct firmware for the furnace.

It's not plug and play.

*You must use the oem replacement for your specific furnace. *


----------



## beenthere

Doesn't look like it comes programmed. Call the place back and ask them.


----------



## sb381

Sorry, I am new to forum. I have seen the threads on the ECM units. I have a thermistor that is bad but the number on it is "SG381". Does anyone know the correct replacement for it?


----------



## beenthere

This one.

https://www.plumbersstock.com/mars-...nEya_GscLyFsTJ39JmKoqQ2lccozceXLKbBoC3_fw_wcB


----------



## luciferdiy223

#CARRIERMAN said:


> Hi mickd & all
> 
> A little information to help all of you with your current and potentially future problems. The blower motor that this furnace use is a D/C motor with an A/C pulse modulator on the back of it. With that being said, this particular design motors job is to deliver a constant CFM supply for the duct system. If you are using a high merve rated filter, this could be a potential cause for the motor module failure. But the most common cause is poor duct design. As I said earlier, this motor will continue to speed up to generate the required CFM. In doing so it also raises the statc pressure on the duct and causes excessive amperage on the motor and controller. This is what causes the majority of the contoller failure. The biggest problem when people retrofit with this beautiful piece of equipment is they never look at the duct to see if it can be used. This particular furnace is a God send for the consumer if the installing company is a knowledgeable one. The most common response you will get from the majority of installing companys is that there is nothing wrong with the duct work, it is the furnace. I have personally installed a great many of these over the years, including the one in my own house. The longest running one I have to date was installed almost 11 years ago with no mechanical failure period! The one in my own house has been here for almost 9 years its self. I cannot stress enough that when selecting a filter, by all means use a pleated filter. There is nothing better in a disposable filter for cleaning and air delivery. But please listen when I say not to use the ones that have the paper looking media. Use the filters with the soft polyester media and change them monthly. But above all, have your duct work calculated for .50 static pressure max including filter. If your HVAC man becomes defensive about your duct problem, find one that is a professional and is willing to fix the problem, not just C/O an expensive control module every year or so.
> 
> Good luck
> Rusty


A lot of info. Thanks for providing anyway.


----------

