# variable speed trane blower motor



## afn63537 (Sep 12, 2011)

Trane XV-80 blower motor just makes thumping sounds like it wants to start, and bumps a little bit at each thump.
The LEDs on the control box don't indicate a problem (if I'm reading them right)
I've read some posts here that state the motor is a DC motor, but the label on it says 115V. (Maybe it's converted inside the motor?)
It does have the big wiring harness going to it, and it IS a variable speed blower, I know that for sure.
I've read here that the parts for these are VERY expensive, and I don't want to dump a ton of cash into a unit that's 12-13 years old.
Has anyone out there got any experience with these units?
I'd be happy to just jumper it to make it a one speed motor, if that's possible.
I've even looked at replacing the fan with a non computer controlled unit, but I was hoping someone might have some insight for me. thanks, doug


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## JJboy (Oct 12, 2010)

Check the wire molex with multiple wires plugged into the rear of motor....
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## kb3ca (Aug 22, 2008)

On the rear of the blower motor is a control module and they can go bad over time. You'll need to get someone to check that out for you.


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## afn63537 (Sep 12, 2011)

*checking the connector*

thanks for the advice.
I'll check that connector now.

no apparent problems with the 16 pin pigtail harness or the 5 pin connector either.

I'll clean the thing, and take my fluke and check the pigtail for continuity.

the motor does have caps inside, because the label on it says to wait 5 minutes before handling after disconnection due to high voltage. no worries there

it does say it's wired for 115V and that it's a "Programmable" motor

I don't see a module on the outside of the motor, would it be inside?
what kind of tester should I make sure the tech has before calling one out if I'm going to have them test that module? 
thanks again


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## JJboy (Oct 12, 2010)

Check this link. http://www.gotoevo.com/ECM products.htm


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## afn63537 (Sep 12, 2011)

thanks for the replies, everyone

the pigtail tests out good

removed the controller and cleaned it

I posted a couple photos of the board and the outside with the Whit-Rodgers info on it at photo bucket at the following location:

http://s1105.photobucket.com/albums/h351/afn63537/

no obvious hot spots on the board, and all the caps are normal.

put everything together and watched LED for trouble codes, and found none

legend says slow flash is "normal with no call for heat"

I turned on the heater, and it blinked fast which is
"normal with call for heat" and the heater started up, but the blower motor still just bumps a back and forth in BOTH directions a few degrees without spinning around

LED indicates everything is normal, but that blower motor just bumps back and forth, even if I let it sit with the fan only on for a couple minutes straight. no difference
Sound familiar to anyone? If I buy the motor, will it come with the module mentioned?
I'll give Johnstone a call tomorrow and find out if the parts are available.
Would a non-Trane tech have the proper tester to test the electronic parts?
thanks to all


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## hvactech126 (Nov 11, 2010)

This is the motor with the module on the end or left side of the picture.







this is the module.


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## afn63537 (Sep 12, 2011)

that's the beast, alright, but I haven't pulled the motor out yet, so wasn't sure what was inside.

do you think the module is a trane only item, and would it be available without the motor?

thanks alot for the photos and insight

doug


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## hvactech126 (Nov 11, 2010)

the module must be a trane furnace model specific programmed and is available separate from the motor. This is NOT a user servicable item. Other than removing the module and seeing burnt components it must be diagnosed by a professional with a techmate tool ( allows you to test the motor and module and determine cause of error).


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## diyorpay (Sep 21, 2010)

Read the Bob Reynolds seminar on variable speed motors.
If you get lucky and can use a soldering iron, this is a possible cause of your problem.

http://www.diychatroom.com/f17/carrier-58mvp-blower-problem-9939/index2/

thermistor thermistor thermistor


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## diyorpay (Sep 21, 2010)

a pic. It's the black disc by the winding, in largest green part of board. Maybe it's not too visible, but it's wrinkled, burned and toasted.


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## JJboy (Oct 12, 2010)

diyorpay said:


> a pic. It's the black disc by the winding, in largest green part of board. Maybe it's not too visible, but it's wrinkled, burned and toasted.


This is the thermistor. Thermistors are resistors that change resistance depending on the temperature at the area around the thermistor. The resistance of the thermistor will increase when the temperature at it increases. They can be used to shut down a circuit or system if overheating occurs. As the heat rises the thermistor will sense it, and increase resistance to a level that will allow very little to no voltage and current.


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## afn63537 (Sep 12, 2011)

You guys rock for taking the time to help, so thanks so much

Is the techmate tool a trane specific tester, or would most techs have one?

Can it be used to diagnose the motor / module when uninstalled, or does it need to be hooked up and tested there?

Soldering isn't a problem for me, so if I find a burnt out cap or thermistor, replacing that would be my first choice, assuming I can order the part readily.

I had to pull the core out of the air handler 2 years ago and find and solder a pinhole in the middle of the darn thing, so this is easy compared to that!

Those pics are awesome, thanks so much.

I'm going to go to that Reynolds seminar in a few minutes and check it out, too!


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## JJboy (Oct 12, 2010)

This website will help you out.

http://www.thedealertoolbox.com/ResidentialHVAC/ServiceTools/Default.aspx


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## hvactech126 (Nov 11, 2010)

afn63537 said:


> You guys rock for taking the time to help, so thanks so much
> 
> Is the techmate tool a trane specific tester, or would most techs have one?
> 
> ...



The motor must be installed to test easily with the techmate. I don't know that all techs would have this tool. In fact I'm not too sure many do. I do, but I'm a tool junkie.


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## diyorpay (Sep 21, 2010)

Just to be clear, in my earlier post, the Bob Reynolds 'seminar' just meant read the attached link. Look for the Bob Reynolds explanation of the thermistor issue.

I can't vouch for amazingkeys site either because I found all this out after the new ECM head had been installed. But I would have tried it if I had known.

http://www.amazingkeys.com/products/search?page=1&s=&search=thermistor


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## afn63537 (Sep 12, 2011)

*techmate*

I first was looking on ebay for the techmate, and then I went to the website and saw they were only $50 new, so sounds good to me. It looks like it plugs right into the module, so I'm assuming it's going to test that also.
I took the blower out and the module off and inspected the boards inside and couldn't find any obvious hot spots or damage, so I guess my best bet is to order the techmate and put the blower back in so I can test it when the tool arrives in a couple days
the thermistor was black on my unit like the photos you sent me, but it doesn't appear burnt.
I'll try and post a pic of it at the photobucket site I used earlier:

http://s1105.photobucket.com/albums/h351/afn63537/
http://s1105.photobucket.com/albums/h351/afn63537/
if I can figure out how to get back there! got it

I'll see if I can post them here like you did, too. doesn't look like that's working, I tried to put one at the end of this and it's just showing a little icon there.

humidity is picking up here (I'm in Florida, go figure)so I've got to get this thing happy soon, or the wife won't be!!
thanks a bunch


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## afn63537 (Sep 12, 2011)

I read where someone jumped past the thermistor. Seems like I could use that to see if it was the cause of the problem of the motor not starting up and just making that bumping sound and moving back and forth with each bump sound.
I'm considering that test, so besides the standard caution warnings so as not to get hurt or burn down the place, any reason not to?

thanks all


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## afn63537 (Sep 12, 2011)

It would seem that if the thermistor is the problem, the motor would not move at all, and also not bump back and forth the way it's doing now.

Anyone ever had one go out and still allow current to flow?

thanks, doug


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## JJboy (Oct 12, 2010)

Replace the thermistor. Radio Shack may have it.


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## Master of Cold (Aug 7, 2011)

Ohhh..the tech mate tester..its not really the best tool for VS motors.
Zebra makes a far superior tester.


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## JJboy (Oct 12, 2010)

Master of Cold said:


> Ohhh..the tech mate tester..its not really the best tool for VS motors.
> Zebra makes a far superior tester.


I just got the TecMate Pro


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## afn63537 (Sep 12, 2011)

*tester info*

You'll have to let us know how that tester works. 

Does it basically replace the main board to test the motor?

I didn't see the 16 wire connector in the photo, though, so do you need to buy an adapter or make one up to use it?

I looked up the zebra, and it seems to be about 5 times as much to buy it, at least it was about 260 on ebay in a buy it now.

thanks


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## JJboy (Oct 12, 2010)

You don't need the extra adapter. TecMate Pro has 16 and 4 pins connector.


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## punchycool (Jan 10, 2013)

The bob Reynolds write above is spot on!! After not getting or finding a tech this weekend with a tester to diagnosis my ECM variable speed motor, I found this thread and took apart the module from the end of the blower motor. I was surprised to find a burned out thermistor described in this thread. The wire on one side is broken completely. I failed to clean my Trane freedom 80 comfort R filters for 12 mos. it was packed with dust. Dumb, yes. 12 yr old unit I had installed and I've gotten lazy cleaning the electronic Honeywell filters and two prefilters regularly.

Can't believe I caused this problem, but with a $1.77 thermistor part (In-Rush Current Limiter (ICL) by Ametherm) I just ordered from Digi-Key Corporation (SL22 1R020), I should be back in business on Tue night. A $56 overnight shipping fee is worth it to me. In fact, I bought 3. I will be finding a reputable servicer who can handle small soldering jobs. Not even sure my std solder or technique would suffice. This part matches my OE thermistor's brand and labeling using the same 20amp max steady state, 1.0 ohm (R @ 25degC), and .015 ohm (R @ Current) ratings.

Luckily the board is solid and intact so no damage to speak of and should make it easy to slip in the new thermistor, bend over the wires, and solder it correctly. 

Original issue for me was a dead blower motor yet a 4 flash error on the IFC, indicating a 'high limit switch' (being tripped). My old limit switch seemed to be going open lazily so I replaced that $45 part but to no avail. Still no blower motor. After thinking more, decided that the limit switch was being tripped because of the inherent high temps in the burner area. Duhhhhhhhh...I then removed the mother board, the IFC if you will, but found no burn marks indicating any issues with that board. I confirmed I have 120V going to motor and 24v coming back. My motor is dead cold though. Not even a trace of an attempt to spin like some folks here speak of. 

Fingers crossed on the thermistor. Will report back with pictures...


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## punchycool (Jan 10, 2013)

...from previous thread...funny thing is that I forgot that exactly 5 yrs ago Dec 2007, my extended warranty through my local installer paid for a blower motor module, for the same concern. That was a $780 bill that cost me just a $50 deductible. 

And eight yrs ago, a then 2 yr old unit(nov 2004), i had the same complaint and under the original warranty, another blower motor module was replaced by my installer. 

Getting old and totally forgot about that correlation. I was out traveling for business A LOT and so my wife had taken care of these concerns. I wonder if it was just another thermistor that popped both times. We will never know. Less the past 12 mos, I've cleaned my four filters on schedule every 6 mos. I don't blame my local tech/installer at all, but Trane...is this a common faulty component??? Maybe I just need to clean the filters every quarter instead......hmmmm. At the end of the day, it's my fault.

Yes, I should have kept renewing my warranty. Lesson learned. I figured it was money down the drain in 2010 and stopped it...funny how those things bite.


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## jdsevier (Aug 20, 2020)

Thank you ALL so MUCH!!!! I just saved more than $2000 and weeks of downtime. No joke. Repaire service wanted to use OEM motor and re-program it, about two weeks out and $2200. I was able to pay the service tech $179 and purchase a new thermistor for $7 (AMETHERM SL22 1R020 NTC THERMISTOR) from Amazon with next day delivery. Cant thank you ALL enough. Oh yes...Forgot to mention, I spent about 4hrs online trying to find a local electronics surplus store to sell me one but no more Ma&Pa shops around anymore.


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