# Loud screeeech from blower motor



## noquacks (Jun 5, 2010)

People,

2010 chevy cobalt LT, ac in ON position 1,2, and 3 do not work at all but when you go to position 4 blower screeches so loudly it hurts my ears. Is it the resistor switch or would you troubleshoot for some other cause?

Now, just a few days ago position 4 actually activated motor ok, and actually blew cold ac, but now, just screeches.

Thanks, people.


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## Windows on Wash (Aug 30, 2011)

Bearings are probably worn out. Probably time for a swap.


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## Bondo (Dec 8, 2007)

Ayuh,.... Sounds like 2 problems,....

There's usually a resistor strip in the air flow that powers 1, 2, 'n 3,...

4 is full 12v power, by-passin' the resistor, 'n I agree, the bearin's are shot in the blower motor,...

So, ya need a new blower motor to run #4, 'n a resistor to run #s 1, 2, 'n 3,...


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## noquacks (Jun 5, 2010)

Thanks, win. So, a bad bearing will prevent the First 3 fan speeds from turning?


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## Bondo (Dec 8, 2007)

noquacks said:


> Thanks, win. So, a bad bearing will prevent the First 3 fan speeds from turning?


Ayuh,... It appears you were typin', as I was answerin' that question,....


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## noquacks (Jun 5, 2010)

Bondo said:


> Ayuh,... It appears you were typin', as I was answerin' that question,....


LOL!! Right, Bond. Guess I need to buy both items. Dang, reststor is easy but not sure how to remove blower motor. Will peek under there, and see if theres a few screws to undo. 

thanks


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## noquacks (Jun 5, 2010)

OK, got the resistor out, but motor is "sealed" in at factory apparently, with melted plastic . Can cut it out, or melt it out. Geez, how dumb. Utility knife could be dangerous if one slips. maybe will try the tip of a soldering iron.........

if anyone has done this before, let me know .....


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## MT Stringer (Oct 19, 2008)

noquacks said:


> OK, got the resistor out, but motor is "sealed" in at factory apparently, with melted plastic . Can cut it out, or melt it out. Geez, how dumb. Utility knife could be dangerous if one slips. maybe will try the tip of a soldering iron.........
> 
> if anyone has done this before, let me know .....


There are some Chevy forums on the internet. Maybe you could find your answer there about removing the blower motor. Or go to the nearest dealership and ask them.

Lucky for me, my wife used to work for a Chevy dealership and we have friends that still work there (parts manager), so sometimes it helps to go ask them and get an idea of what is involved, then decide to tackle the job or let them do it. :biggrin2:

EDIT: Apparently you aren't the first one to have this problem.

https://www.google.com/search?q=how+to+replace+blower+motor+on+chevy+cobalt&ie=utf-8&oe=utf-8


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## noquacks (Jun 5, 2010)

Great, now I did it- cut out the blower motor with a hacksaw, and the dang thing works!! No screech, no grinding of bearings, perfectly smooth motor! Sheesh.

Now, I gotta jury rig a bracket to screw it up back in there. Also, yanked the resistor, and for the heck of it I turned on the motor control knob and it works well when on 4 (1,2 and 3 still don't work). Can a motor work without a resistor? 

Finally, I popped the resistor back in, turned on the motor switch, and again, 1,2,and 3 don't work, and 4 works well. Still bad resistor? Cant figure out why motor screeched before. what did I get myself into......


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## Bondo (Dec 8, 2007)

> Finally, I popped the resistor back in, turned on the motor switch, and again, 1,2,and 3 don't work, and 4 works well.


Ayuh,... Are you readin' what's bein' written,..??


> There's usually a resistor strip in the air flow that powers 1, 2, 'n 3,...
> 
> *4 is full 12v power, by-passin' the resistor*, 'n I agree, the bearin's are shot in the blower motor,...


Do you have a multimeter or test light,..??


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## noquacks (Jun 5, 2010)

Bondo said:


> Ayuh,... Are you readin' what's bein' written,..??
> 
> 
> Do you have a multimeter or test light,..??


Thanks, Bond. Yeah, I'm reading. But now I understand that 4 is open , full 12v. Makes sense. 

So, if youre convinced bearings are bad, why the smooth motor after I sawed it out? Maybe the motor has a better angle, and bearings run better until the motor goes upside down and then the truth shows itself again with the screech?

thnaks


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## Bondo (Dec 8, 2007)

> Maybe the motor has a better angle,


Ayuh,.... Position of the motor, 'n load on the fan will no doubt effect the bearin's,....

Kinda like how a gyroscope is hard to turn over in yer hand,....

With the ridiculous effort needed to pull the motor, I'd just replace it,....
Never seen one that couldn't be unbolted,...
Might have to take a dash out, but things were bolted together,...

The resistor can be Tested, which is where I'd start,....


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## MT Stringer (Oct 19, 2008)

HMMM...I guess my link to the Cobalt forums wasn't much help to you, huh?


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## noquacks (Jun 5, 2010)

Bondo said:


> Ayuh,.... Position of the motor, 'n load on the fan will no doubt effect the bearin's,....
> 
> Kinda like how a gyroscope is hard to turn over in yer hand,....
> 
> ...


Fixed the motor, whew. Turns out there is no bearinmg- its a bushing. It was kinda rusty/stuck, so I sanded it down, and put anti sieze on it. Yup, no way to unbolt/unscrew this one, bond. Gotta cut/hack it out, sounds incredible. 

So, other than trying out the switch knob, how do you test a resistor? Voltmeter? Ohmmeter? This resistor is not like anyone I ever saw before- has no copper coils. Its a flat circuitboard like thing.......


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## noquacks (Jun 5, 2010)

MT Stringer said:


> HMMM...I guess my link to the Cobalt forums wasn't much help to you, huh?


Yes, it was!! It provided a youtube as well! Thanks!


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## Bondo (Dec 8, 2007)

> So, other than trying out the switch knob, how do you test a resistor? Voltmeter? Ohmmeter? This resistor is not like anyone I ever saw before- has no copper coils. Its a flat circuitboard like thing.......


Ayuh,... I Don't know yer car, 'n was Amazed in MT's link, that ya gotta cut the motor out,....

I'd think the resistor should have (+) Power goin' in, 'n an out wire for #1, #2, 'n #3,....
A test light oughta tell ya, but again, never seen yer car, nor anything like it,....


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## noquacks (Jun 5, 2010)

Well ended up I had to buy a new resistor cuz time was running out for the weekend, and son needs the car tommorrow, and yippee, new one works, so old one had to bad. All woks wel now. Big thanks to allhere as usual, who helped out. Really.


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