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George H.
George H., ASE Certified Technician
Category: GM
Satisfied Customers: 18664
Experience:  15+years ASE Master W/L1 Drivability
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2006 GMC: my a/c blower motor just stopped blowing..speeds

Resolved Question:

2006 GMC Sierra 8 cylinder
One month ago my a/c blower motor just stopped blowing. All 5 speeds.
I pulled all the panels fron the inside. Looked around a little. Went under the hood to the fuse box. Pulled the fuse, inspected it, it looked fine, I replaced it.
I went in turned the key on and the a/c fan took off has worked perfect until today. It stopped dead. I pulled and checked the fuse again and nothing. The compressor is working because when you are going over 30 mph crack a window you can feel cold air. I am not too much of a mechanic but have no money so I can learn.
What should I do?
Submitted: 5 years ago.
Category: GM
Expert:  George H. replied 5 years ago.

Hello I will help you with your question,


Take a look under the right side of the dash and pull the sound panel so you can inspect the blower and blower speed control wiring for burnt/melted connections. If you don't find any you will need a 12 volt testlight or a voltmeter to check where you are losing power.


Let me know and I will guide you through the testing





Customer: replied 5 years ago.
It is dark out now, I will do this first thing in the morning. When will you be back online?
Expert:  George H. replied 5 years ago.

I will be near a computer from about noon ET until 10 or so. Let me know what you find.


If you don't have any burnt/melted connections check the red wire for power, then the large purple. Have the key on and the blower selection on high when you do this, use a straight pin to probe into the connector so you can leave it plugged in.


Let me know what you find and we can work from there





Customer: replied 5 years ago.

ok I will be back with you tomorrow. Thanks


I am not sure what you mean "use a straight pin to probe into the connector so you can leave it plugged in".

maybe it will be evident when I see the connector.

Customer: replied 5 years ago.
ok I do get what you mean to use the straight pin as a conduit. Sorry I'm old and slow
Expert:  George H. replied 5 years ago.

Let me know what you find!




Customer: replied 5 years ago.

I didn't see any melting or any heat looking damage. I do sort of recall afaint odor yesterday.

I sort of wiggled the housing that the two wire harnesses plug into. The fan started back up.

So at this point I have a/c again.

I am going to click to pay but can you give me your take on what caused this to happen twice now. I kow it is speculation but if it happens again what would you suggest. What should I do next time? I undid the two scews that held the housing and checked out the sensor lookig deal. What is that called. do you think it is slowly going bad or did I just lose connectivity in the harness plug?

Thanks for your help.

Expert:  George H. replied 5 years ago.

I think you need to replace the blower speed controller. This is a transistor that can fail with heat and give you the symptoms you are experiencing. That is what you would be testing to see if you have power on the red wire and the controllers job is to pass that power to the purple wire of the blower motor so it is failing internally. Remove the three screws and the controller will drop out of the blower case.


Let me know how I can help you with this


Thank you



Customer: replied 5 years ago.

So the transistor fails and the power from the red wire does not transfer to the purple wire. But when I wiggle the blower speed controller (is this also called the resistor?) the transistor get conductivity again and works until it gets hot again at some later time and fails again. Is this what it looks like to you?


So next time it stops working I check the red wire, if it is hit I check the purple. If the red is hot and the purple is not then the controller is bad. And it looks simple to change it out.

Anything in particular to look for at that point? Thanks

Expert:  George H. replied 5 years ago.

You understand the problem and the repair. The only thing I have run into other than this is that the connector will get burnt/melted so be sure to inspect it closely and replace the connector if it is burnt along with the controller.


Let me know what I can do to help you


Thank you



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