Blend Door Actuator Head Scratcher

I have an '07 Silverado Classic with dual manual climate controls. The drivers' side control has been having trouble 'finding' new temperature settings. I can hear the blend actuator spinning and spinning every time I move the temperature lever. Sometimes it never stops.

So, I'm in the driveway doing some troubleshooting. I have the key on 'run' and the engine off. The passenger side actuator quickly finds its new position. Now, I try the drivers' side, and it works, too!

In the end, I'm finding that the blend door actuator seems to be working when the engine is off, but not working correctly when the engine is running. What could the problem be?

Perhaps the gears in the blend door module are stripped, but it takes a higher voltage from engine running to give it enough energy to actually slip the gears. When running off battery, not enough voltage. Just guessing.

Problem solved! The truck was totaled in a head on collision. My wife and I both walked away.

Problem solved! The truck was totaled in a head on collision. My wife and I both walked away.

Glad to hear you got it fixed! Oh...Glad to hear you are both OK also!