Actuator problem ??

[Jeff in Virginia]

I have a 04 GMC 2500 HD 4x4 Duramax 4 door. I can get air to blow thru the defrost and floor but not the vents for cab. Where is the actuator located for the vents or is there anything else I need to check.

Thanks.....

Jeff in Virginia

[Formulabruce]

Blend motor  is on pass side under dash, just to the right of the hump. Could be the encoder on the motor or the blend door is stuck. I think A1A auto has a video on this on you tube.

[Jeff in Virginia]

Thanks a bunch, I'll check it out in the morning.