Originally Posted by billmerserve

For what its worth department, I repaired and replaced everything to get heat, with limited success, on an 84 300d. What finally fixed it permanently, was replacing the controller behind the glove compartment. As it turned out, that was the easiest repair I did on the car. I plan to take the old one apart one of these days to see if the board can be repaired.

Originally Posted by rocky raccoon

Thanks. This one never occurred to me.

Originally Posted by tangofox007

It occurs to me that, if your heat doesn't work with the monovalve unplugged, the problem cannot possibly lie with the temp controller.