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GM Bob
GM Bob, ASE Master Technician
Category: GMC
Satisfied Customers: 1104
Experience:  30 plus years experience as GM technician, ASE Master Technician and GM Certified
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I have a 02 gmc Yukon denali xl 6.0l my front blower motor

Customer Question

I have a 02 gmc Yukon denali xl 6.0l my front blower motor was not working. I replaced that. it still does not work. the old motor works when hooked up to a battery. the resister module has 3 wires going into it orange thin gray and a black. It has auto
climate control. I have no power to the module. when using a test light the black wire seems to be the ground. checked all fuses all are good. thank you. mike.s.
Submitted: 2 years ago.
Category: GMC
Expert:  Gary replied 2 years ago.
My name is Gary
I am sorry for the long wait
at the module does the orange wire show 12 volts at it ?
if NOT then in the under hood fuse box can you see if the fuse called FRT HVAC a 30 amp fuse shows 12 volts at both sides of that fuse testing it in place through the little openings in the tops of that fuse ?
Customer: replied 2 years ago.
that fuse had power on both sides and there is no power to the orange wire
Expert:  Gary replied 2 years ago.
ok thank you for checking
the problem is going to be the orange wire is broken or has a bad connection between the under of that fuse box to the module
its best to first check this connector here C296 alot of times the terminal in that connector for the orange wire is melted or bad
if that connector turns out good then its a matter of following that orange wire from that connector to the under hood fuse box to see where that wire is broken or damaged or bad OR run a new wire from that fuse to the module
once that orange wire has its restored 12 volts the blower should work just fine
cut and paste this link for a picture of that connector location!954&authkey=!AOD58gWHd0WJndM&v=3&ithint=photo%2cgif
Customer: replied 2 years ago.
ok I skinned the orange wire and hooked it up directly to the battery and now theres power there but I still have nothing the c296 connector is in good shape not melted or corroded and theres power at the connector. the ground is good as well
Expert:  Gary replied 2 years ago.
so you put 12 volts so the orange wire now has 12 volts and the blower will not run at all ?
Customer: replied 2 years ago.
that's correct right from the battery. I didn't confirm exact volts but I used a test light and it lights up
Customer: replied 2 years ago.
ground is good gray wire has nothing not sure what that's for
Customer: replied 2 years ago.
what do u suggest now
Expert:  Gary replied 2 years ago.
the grey is the control form the blower switch
with the key ON and the blower set to high what does the grey read ?
Customer: replied 2 years ago.
with 12 volts from the battery to the orange wire and the switch on high I get no voltage on the grey wire.
Expert:  Gary replied 2 years ago.
with the key ON and it set to high no volts at the grey at all ?
that grey wire should shoe like 2 or 2.5 volts with the key ON and the blower set to high
Customer: replied 2 years ago.
With key on blower set to high. I get .36 volts.
Expert:  Gary replied 2 years ago.
then when you have the key on and turn it to low or off what does it read ?
Customer: replied 2 years ago.
with the switch off it reads 4.37 volts on the gray, low is 3.4 volts and medium is 3.7 volts and high is .35 volts. While checking the voltage the blower went on for a few seconds and stopped. Still taking power from the battery direct to the orange wire.
Expert:  Gary replied 2 years ago.
are you sure the terminals in the resistor and at the blower motor are good ?
if you wiggle them will the blower come on ?
if this started to run when you were testing you moved a terminal or wire
Customer: replied 2 years ago.
In the beginning my blower slowly stopped working. It would work for a while and then not work at all. I checked all the connections and wiggled all the wires I could, and this is why I replaced the blower motor in hopes that it was that causing this problem. That's the first time it has kicked on since last summer and it stopped after a second. I wiggled all the same wires and it did not come back on. When the orange wire is jumped to the battery there is a spark like there is a load on it.
Customer: replied 2 years ago.
Gary I haven't heard from anyone in 2 days.mike
Customer: replied 2 years ago.
Gary,I still haven't heard from anyone.Mike
Expert:  GM Bob replied 2 years ago.
Hello my name is ***** ***** for the wait.
Please let me know if you still need help.
If not I will close this question.
Thank you
Customer: replied 2 years ago.
I donot know if I should replace the module or the swich.You can see from previous questions I got different voltages on each switch setting on the grey wire.The orange feed wire I jumped right off the battery.The black wire was ground.I would appreciate any help you can give.Mike
Expert:  GM Bob replied 2 years ago.
When you jumped the fan did you use both Ground and hot. That went to the blower controller?
Here is a schematic
Terminal A and C at the controller to the two wires that go to the fan.
Does the fan run?
Sorry is I'm asking the same question from above post.
Customer: replied 2 years ago.
I took the blower out and hooked it up to a battery and it ran fine.Put a new one in anyway since I had bought it.With power from the battery I checked the ground with a test light.It was fine.What is the most common problem with the blower system on these cars?
Expert:  GM Bob replied 2 years ago.
A test light is a ok test.
I wish you would see if the fan will run on the ground going to the fan controller.
The fan controller is the most common problem. Not the heater control
Customer: replied 2 years ago.
when you say fan controller do you mean the switch.mike
Expert:  GM Bob replied 2 years ago.
The fan controller is called Blower Motor Control Processor.
Here is the picture of it
This is where I wanted you to jump the ground and power to the fan.
Expert:  GM Bob replied 2 years ago.
Did you get your fan working?
Let me know if you need more help.
Thank you

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