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Eric, Automotive Repair Shop Manager
Category: Buick
Satisfied Customers: 32071
Experience:  20+ yrs. experience as repair shop manager and technician.
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2002 buick: Blower fan will not work on defrost..outside temperature

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My 2002 Buick's air handling is not working. Blower fan will not work on defrost, heat, etc. I'm in Cedar Rapids, Ia and the outside temperature is 22* F. Is it likely that this is a simple issue or a complicated one, please?

did you lose all speeds at one time on the blower motor, or did you lose the lower speeds first?
Customer: replied 5 years ago.
Thanks, XXXXX XXXXX speeds were lost at the same time.

ok, this will be either the blower motor or blower motor controller processor(resistor).

They are both located behind the right side of the instrument panel.

Remove the lower trim panel:

Once you do this, disconnect the harness connector to the blower motor. With fan speed on low, check voltage. It should be 5-5.5v. now turn fan switch to next speed. voltage should increase. Do this until you are at high fan speed. the voltage should be at 12v.

If it is, then replace the blower motor. It voltage doesnt increase then it is the control processor.

if blower motor, disconnect screws to it and drop down from the housing to remove and install new one:


If the control processor, drop the glove box for better access and remove the connector to it, remove the one retaining screw and remove processor and install new one:


in case it is the processor, here is how to remove the glove box for easier access:


unless you have any further questions on this, I am getting ready to go offline for the evening, so please let me know if you need clarification on the directions
Customer: replied 5 years ago.
Thanks again, Eric. My car is outfitted with "Dual Automatic ComforTemp Climate Control. Does this new info make a difference?

no, the location of the blower motor and control processor are the same, as well as how to test the blower motor to see whether the blower motor is faulty or the control processor is faulty.
Customer: replied 5 years ago.
Thanks. It's pushing midnight here. And it's time to get some rest. I'll try your suggestions and tips as soon as I can. More feedback another day. Thanks again, Mike.

sounds good.
Customer: replied 5 years ago.

Hi Eric, since our last discussion, my 2002 Buick has been driven on 11 outings. The air handling system has worked twice. There seems to be no rhyme or reason for why it worked on 2 occassions and failed on all the rest.


You're the pro and I appreciate your help, but what do you think about this issue with this new information, please. Don't ya just love intermittent problems..??? Aaarrgh!


ok, two possible causes. loose connection/wiring at the blower motor or a dead spot in the blower motor.

turn blower on and try wiggling the wiring harness to it, as well as wires at the connector. If it starts working, then you will need to repair wiring at connector.

If not, then this is a dead spot in the blower motor and replace it
Customer: replied 5 years ago.
Thanks Eric. I'll follow your suggestion and get back to you in about an hour. Mike

sounds good
Customer: replied 5 years ago.

Hi Eric, Now the score is 3 out of 15. Yup. It's been driven 4 more times and worked once.


Where the heck is the wiring harness and blower motor? I made a quick inspection. The engine compartment and firewall are not like my 71 Chevy...


I stopped at the auto parts store and they had a blower motor that I could get - which I did and return if that's not the problem.


it is behind the right side of dash. there is a lower trim panel you remove and look up behind the dash and you will see the blower motor

trim panel to remove:


blower motor:
Customer: replied 5 years ago.
Alsooooooooo. The coolant level is low. Just thought I should mention that...

coolant level will not affect the performance of the blower motor.

Being that this is a 3.8l engine, check around the base of the intake manifold for small puddle of coolant as they are notorious for leaking at the intake manifold
Customer: replied 5 years ago.
Thanks again, Eric. Realizing that the blower will not run until the coolant has reached a certain temperature - with the fancy control panel & the mode set to "Auto" - I thought I had better mention it.

this would affect it only if the blower doesnt work on heater, but does work on AC. If not working on either, then not an issue
Customer: replied 5 years ago.
Sheeesh! Seems like your answers make perfect sense! Smile Thanks a ton, Eric. I'm heading out to lay down under the trim panel. Back atcha later. Mike

ok, sounds good and keep me posted
Customer: replied 5 years ago.


1. I removed the trim panel per instructions.

2. Slithered into the foot well - oh my aching back.

3. Turned ingnition to on and the blower spun. (4 out of 16)

4. Wiggled and jiggled the wires (thin brown, purple w white stripe, black) and the fan would sputter.

5. Seperated the wire harness. Tough to do.

6. Re inserted the wire harnes.

Now get this.

7 Wiggled and jiggled the wires (a LOT!) and can't get the fan to sputter. It just keeps spinning.


Whaddya think?


ok, either you had a wire loose in the connector that you managed to get seated better when you were wiggling them, or the connector was just not secured enough.

I would leave the trim panel off and drive for a few days and see if it sputters or quits again. If it does, then we will need to get a new connector at a dealer and splice it into the harness after you cut the old one off.
Customer: replied 5 years ago.
Terrific! Way ta go, Eric. I really appreciate your help - and your focus. Thank you, XXXXX XXXXX

glad to have helped and have a Merry Christmas and safe holiday season
Eric and other Buick Specialists are ready to help you
Customer: replied 4 years ago.

Helloooo Eric,


We last visited as Christmas approached. Now Thanksgiving is here. I hope you are looking forward to the Holiday.


About the fan in my 2002 Buick, since we talked I have put up with the intermittent performance of the fan for 11 months. It would have its spells of being ornery and not spinning, but for the most part it behaved at a performance level that was tolerable.


Then it stopped and would not restart.


I extracted the fan motor from the dash assembly. While trying to test the fan I was handling, turning, and tipping the fan motor assembly. There was a fine black powder that kept coming out of the assembly. Hmmm?


What was/is the powder?


Does that point to or confirm the cause?


Finally the amout of black powder that would fall out diminished. I reinstalled the fan. It both works and fails. But, I think it works slightly more dependably.


What is your conclusion, please, Eric?


What needs fixed?


The black dust is from the magnets surrounding the armature wearing, which is a normal wear item. The dust may have accumulated and prevented good contact between the armature and magnets, and now have a better contact so working more often, but with the magnets wearing enough to produce that amount of dust it does mean it will fail completely sooner rather than later.

I would go ahead and replace the blower motor at this point
Customer: replied 4 years ago.

Outstanding, Eric!! A replacement unit from auto-parts retailers has been quoted at $240 - $280.

I was slow to pull that trigger without some confirmation.


What about... used parts?


What about... Thanksgiving?


If you go with used, make sure it has a guarantee on it, and I would even have them test it with a direct 12v source to make sure it is good.

If you want to go with new, you can get one for $115 from I have used them before with good success. below is link to the one for your vehicle

Have a great Thanksgiving and rest of the Holiday Season!

Customer: replied 4 years ago.



At O'Reilly's their rep brought out those 2 assemblies. I had my blower motor and mine looks different from those 2.


At Advanced Auto, their rep found 3 fans on their system. The same 2 just discussed, plus one that...

- looked like mine,

- looked like the diagram you sent on Tuesday, December 13, 2011 3:44 PM EST, and

- was way more expensive (Advanced Auto = $240. NAPA = $280).


What do you think, my friend?


I know there were a couple of different styles used in that year.

check all the selections to see which matches:
Customer: replied 4 years ago.



I'm not sure about which replacement blower motor to buy. But, but, but that is not your issue. I'll work through it and get the right one.


You provided the terrific answer that the blower motor was the culprit. Thank you, XXXXX XXXXX thank you, Eric.




you are very welcome and have a great holiday season!
Eric and other Buick Specialists are ready to help you