Air vent problem 03 yukon slt

bedmonds1 · July 25, 2006

I installed an aftermarket ipod interface behind the radio. I pulled the fuses in the engine compartment for HVAC, Radio, and Radio amp and removed the radio and AC controls from the dash. I installed the unit (which worked ok), plugged everything back in, but then, when you start the truck, the air comes on, starts at the feet vents, goes to the dash vents, then goes to the defrost vents and stays there. No control adjustment moves it to the dash vents, maunal or auto. There is a little bit of air coming out of the foot vent. Once the truck is running, if you turn off the air completely then turn it back on, it does not cycle from the floor to the defrost, but it starts in defrost and stays there. I went back in and removed the ipod unit completely but I am still having the same problem. Please Help! Thanks!

ChevyTech007 · July 25, 2006

The fix "may" be very simple. When a control head is connected it goes through a 1 minute recalibration period. No controls should be touched until it is done. I would disconnect the battery for at least 10 minutes, then reconnect and turn ignition on and let it set for a couple minutes without touching anything. If that dose not fix it you will need to have it scanned for codes. Below is a bulletin that might apply. I know it will not copy the picture so the area it describes is behind the glove box. Post back with how it goes.

Subject: HVAC System Cannot Be Controlled Or Defaults To Defrost Mode (Repair HVAC Actuator Harness) #04-01-38-008 - (06/17/2004)

Models: 2003-2005 Cadillac Escalade, Escalade ESV, Escalade EXT

2003-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2003-2005 GMC Sierra, Yukon, Yukon XL

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Condition

• 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.

Correction

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.

bedmonds1 · July 25, 2006

Thanks, I will try it. Now I have another problem. What is the constant 12v wire on the radio harness and what is the ground? Do you have a diagram? Thanks again!

ChevyTech007 · July 25, 2006

The always hot wire is orange position B1, the ground is Black with White tracer position A12. If you are looking at the face of the connector (that plugs into the radio) B1 is on the bottom row all the way to the left. A12 will be on the upper row all the way to the right.