Alright, so I have one more thing to add, I just warmed the engine up enough to get the juices flowing. I felt the hoses leading into and out of the hot water valve. One side (going in) was hot, the other (going out) was cold. The plunger device inside of the valve seemed to move pretty easily when cold, but seemed frozen once the engine was hot. I hope that this might preclude an A/C mode switch problem, but I'd like to hear what anyone has to say. Thanks once again, John Weaver ETDOC RED DMC #10527 [Non-text portions of this message have been removed]