2002 GMC 2500 HD ac issue.

[olduner]

Hey guys, the knowledge on this site always amazes me. After pulling out and changing my old head unit, my AC dash vents no longer blow air. Air comes out of the defrost vents, my back seat vents and the floor/leg vents, what did I fuck up??? A lot of wires had to be pushed back into the dash, along with the old OnStar module.

 

[Flying_Lavey]

Hey guys, the knowledge on this site always amazes me. After pulling out and changing my old head unit, my AC dash vents no longer blow air. Air comes out of the defrost vents, my back seat vents and the floor/leg vents, what did I fuck up??? A lot of wires had to be pushed back into the dash, along with the old OnStar module.

The diverter on those trucks will get stuck in defrost at times. I had the same thing happen in my '01. I crawled under the dash (I believe with the A/C cover off) and gave the big ring gear a small turn away from the stop and it went back to normal and never gave another issue.

 

[Flying_Lavey]

I have always suspected it was caused by the diverter being in a different position than the selector know when it is put back in. Like it was on dash when you took it out but unknowingly was on floor when put back. Causing the 2 to be out of sync.

That was my philosophy at least. Never tested nor looked into it enough to determine if that was accurate.

 

[SBMech]

All you replaced was the control panel?

Disconnect the battery for a few minutes and see if it will reset it.

It's possible you got a bad reman or unit too, why did you replace the original? After market units are always suspect to weird issues or DOA.

 

[olduner]

All you replaced was the control panel?

Disconnect the battery for a few minutes and see if it will reset it.

It's possible you got a bad reman or unit too, why did you replace the original? After market units are always suspect to weird issues or DOA.

It was a older stereo head unit in dash.

 

[thedan]

Maybe knocked off a vacuum line(if they are vacuum controlled)? The default is defrost when that is the case.

 

[Flying_Lavey]

Maybe knocked off a vacuum line(if they are vacuum controlled)? The default is defrost when that is the case.

They are 100% electronic.

 

[USMC2010]

I have replaced all 3 of the motors in my 2002 Silverado, 2 of them 2x. the vent one is behind the stereo and lower. You can see it up and to the right of the gas pedal lever. It's not hard but it's not fun either.