2007 GMC Yukon Blower Fan

Tiny
YUKON DAN
  • 2007 GMC YUKON

Air Conditioning problem
2007 GMC Yukon V8 Four Wheel Drive Automatic 78,000 miles

The front Blower fan will not work for air conditioning or heater. The rear blower fan works fine. The fan does not work on auto setting or when trying to increase fan speed manually. The indicator lights indicate the fan speed is increasing but it will not kick on. I could not find the location of a fuse or relay for the blower fan in the owners manual. Any ideas?

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Friday, October 2nd, 2009 AT 6:22 PM

14 Replies

Tiny
RASMATAZ
  • MEMBER

Check and test the blower motor control module in bottom center of HVAC modules.

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Friday, October 2nd, 2009 AT 6:30 PM
Tiny
YUKON DAN
  • MEMBER

Where is the HVAC modules located? Engine compartment? Behind dash?

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Friday, October 2nd, 2009 AT 6:37 PM
Tiny
RASMATAZ
  • MEMBER

Its on no.8 see below


http://www.2carpros.com/forum/automotive_pictures/12900_blower_motor_control_module_1.jpg

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Friday, October 2nd, 2009 AT 6:46 PM
Tiny
YUKON DAN
  • MEMBER

Checked module and it had 12 volts on the input but only 1.2 volts on the output to the motor. The module also became warm or hot to the touch. I purchased a new module and plugged it in but the blower still does not work. Apparently the modudle was not bad so where should I go from here?

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Monday, October 5th, 2009 AT 10:48 AM
Tiny
RASMATAZ
  • MEMBER

Disconnect the module and power the motor direct from the battery and see what happens

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Monday, October 5th, 2009 AT 3:54 PM
Tiny
YUKON DAN
  • MEMBER

Took the 12 volts off of the incoming plug to the blower module and jumped it to the two wires going to the blower motor. The motor ran. This was done with the blower module out of the circuit Tried picking up power off the output side of the blower module (which showed 12 volts on the tips, this is where the blower motor would be plugged in) but it would not run blower? It seems the small purple and white wire coming into the blower module is not letting the motor run. Any suggestions

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Tuesday, October 6th, 2009 AT 2:13 PM
Tiny
RGREEN477
  • 1999 GMC YUKON

Heater problem V8 Four Wheel Drive Automatic 177000 miles

Issue: Drove the truck to destination and blower worked fine when truck was shut off. Got in it to leave and turned on heat on but no blower. Blower does not run in any of the four positions of the Control Switch. I have checked fuses but all are good. I originally suspected it was the blower motor but now am stumped!

Took the fan motor out and tested voltage. Here's what I saw which, to me, is strange.

There are four "knotches" on the rotary switch corresponding to fan speed. Right? Defined in the schematic as Lo, M1, M2 & Hi. Below is the voltage I see at each setting using a digital meter.

Off - Zero Volts
Low - 8v but climbs slowly to about 9v
M1 - 11.7v
M2 - 11.45v
Hi - Zero Volts
Note: When I turned to a lower setting from any higher setting the voltage drops dramatically and then slowly climbs back to the values from above.

I have now replaced both the Fan Motor, the High Blower Relay with no avail or change in voltages.

I removed the Blower Resistor and check for continuity across all of the various coils and the one resistor. All are good.

The only thing I have not replaced/tested is the HVAC Control Module which includes the rotary switch.

Other notes:

I have checked wiring harness around the heater housing for signs of overheating. No visible signs.
Change other rotary switch for air deflection and the appropriate doors open or close. I can hear them.
The Recirculation button works fine as I can also hear/see the door operate.
Rear AC fan works fine.

Questions:

1. I understand a common problem is that if the resistor goes bad, the fan may only operate on Hi. I am seeing the opposite. Should I be seeing continuity across all poles on the resistor?
2. Couldn't I hook the fan to a 12v power source and it should run? Haven't done it yet, afraid of frying the brushes but seemed like a basic test.
3. Should the HVAC Control Module be the next focus? Is it a pain in the butt to remove?
4. Am I delving too deep here and missing something obvious?

So I'm somewhat stumped. Wondered if you had any specific recommendations based on the above info.

Thank you in advance. Hope you had a great Thanksgiving.

RG

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Thursday, August 3rd, 2017 AT 4:44 PM (Merged)
Tiny
2CARPROS KEN
  • ADMIN
  • 9,386 POSTS

Hello,

It sounds like you have lost power somewhere and it could be the controller but lets run some test to be sure.

Here are some guides to help you get the problem fixed.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

Here are some wiring diagrams to help with the testing (Below)

Please let us know what happens.

Cheers, Ken

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Thursday, August 3rd, 2017 AT 4:44 PM (Merged)
Tiny
MNSKUNKY
  • 2004 GMC YUKON
  • 6.0L
  • V8
  • AWD
  • AUTOMATIC
  • 112,000 MILES

About a week ago I noticed that my fan quit working for about 5 minutes one day. Then a few days later it happened again. Today I tried to run my a/c on full blast and it started pumping out heat. So I turned it off and back on. Now the fan will not work at all anymore. Do you have an idea if it is the blower motor, blower controller, or the resistor?

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Thursday, August 3rd, 2017 AT 4:44 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
  • 30,991 POSTS

Without testing no dont know what it is could even be a loose connection to the blower motor itself. Do you have a multi meter to do some testing? Also do you have auto climate control or manual ac controls?

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Thursday, August 3rd, 2017 AT 4:44 PM (Merged)
Tiny
CHICOR
  • 2005 GMC YUKON

Air Conditioning problem
2005 GMC Yukon V8 Four Wheel Drive Automatic 80000 miles

Fan will not operate to the air conditioner. Is this a fuse issue, something I can replace or will it require repair.

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Thursday, August 3rd, 2017 AT 4:45 PM (Merged)
Tiny
RHALL77
  • MEMBER

Does the fan come on otherwise. If not check and see if the fuses are blown. If they are ok, disconnect the fan and use a test light to see if there is voltage there when the AC is turned on.

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Thursday, August 3rd, 2017 AT 4:45 PM (Merged)
Tiny
ZONEPILOT
  • 2004 GMC YUKON

Heater problem
2004 GMC Yukon V8 All Wheel Drive Automatic 40000 miles

Blower motor does not work in the front fuses are good and fan is free is there a relay or something that is not working.

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Thursday, August 3rd, 2017 AT 4:45 PM (Merged)
Tiny
JDL
  • EXPERT
  • 16,292 POSTS

Welcome to the forum, did you use a testlite to check fuse circuit? Not sure if that is readable? At the blower motor connector, purple wire is voltage and black wire is ground. You can use testlite to check for voltage.


http://www.2carpros.com/forum/automotive_pictures/170934_04_yukon_1.jpg

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Thursday, August 3rd, 2017 AT 4:45 PM (Merged)

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