Auto Repair Q&A



Cooling System










Auto Repair Products

I drive a 2004 GMC Yukon. It has independent temperature controls for driver and passenger, The passenger side does not respond to temp set for cooling and is often blowing warm air? Thanks

sounds like the passanger

sounds like the passanger blend door servo motor or a stripped door spline. can you hear any thing moving in the heater housing when you move the lever?

Actually no levers, An

Actually no levers, An electronic dial for each side set to a temp.

ok, do you hear anything when

ok, do you hear anything when the knob is turned?

No there is nothing unusual

No there is nothing unusual as far as any noise, the problem is also intermittent. It will be working fine one minute and blowing warm air the next.

Because everything is electronic I'm wondering if the control module is bad?

thanks much for your time.


i've found a bulltin on

i've found a bulltin on control problem, here's the info with out pics, they donn't post here, let me know what you think, if you want the pics, post an email ad.

Bulletin No.: 04-01-38-008

Date: June 17, 2004


HVAC System Cannot be Controlled or Defaults to Defrost Mode (Repair HVAC Actuator Harness)

2003-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2003-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003-2005 GMC Sierra, Yukon, Yukon XL


^ Some customers may comment that they cannot control the HVAC (heating, ventilation and air conditioning) system. Others may comment that the HVAC system defaults to the Defrost mode.

^ Technicians may find that the following diagnostic trouble codes have set:

^ B0229 Recirculation Actuator

^ B0414 Left Air Temperature Actuator

^ B0424 Right Air Temperature Actuator

^ B3770 Mode Actuator Cause

The HVAC actuator harness may contact a sharp edge on the instrument panel support brace, causing a rub through condition and a ground out of the actuator control and/or feedback circuits.


Locate the HVAC actuator harness contact point shown by the arrow in the above illustration. The illustration is of the instrument panel with the instrument panel compartment door opened and folded downward. The actuator harness is located in the left side of the opening in the instrument panel.

Technicians are to inspect the HVAC actuator harness for contact with the instrument panel support brace. Repair any damage to the actuator harness wiring and install protective plastic conduit over the harness. Install friction tape over the sharp edge of the instrument panel brace. Clear the diagnostic trouble codes and verify proper HVAC system operation.

Warranty Information

For vehicles repaired under warranty, use the table.

I think it's worth a

I think it's worth a shot.

Once again thanks for your time.

[email protected]

check email, let me know

check email, let me know

there is a bunch of mechanics

there is a bunch of mechanics who read the questions that would be more than happy to help you with your question


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Bob, It's been more than a


It's been more than a week since we've seen a response from you. Do you still need help?