gusthecoon

Hi,

2004 Tahoe. I have a knock in the dash.

• Switch off the AC compressor knock still there
• Switch off the AC fan knock still there.

If i move the temp control from cool(blue) to warm (red), knock goes away. I'm thinking vent door actuator, but i'm not certain which one or how to get to it.

thanks
Gus

MDTAHOE

Definitely sounds like the blend door motor (actuator) I believe it is fairly simple. Lean under the dash and listen to where it is coming from . You will be able to feel it if you put your hand on it.