I have replaced mine twice as well. GM is the only one who has the actuator.Mine does this also. And its the heater control valve. I've had mine replaced 3 times and now its messed up again. Whats the fix for this whitout going to gm?
Sounds similar what year truck? Also see if you take off real fast if it does it or stopping real quick should do the opposite.wow.. good thread. I have a similar problem. I can be crusing down the road with the a/c on and the on the drivers side the heater will start blowing HOT air but the a/c stays on the pass side. The only way to fix it is to turn the IGN off and restart it and all it well again. Could this be related to that valve?