Blower running HOt at all time.

[Basstrip]

I need advise please, I have a 92 300SD and the air is running hot at all times. (except when air supply button is push it in at center vents). Allso the CCU driver side control screen reads 57F when knob is set max cold or reads HI at any other seeting. Any body the knows what's going on, please advise. I can not control air temperature, just the volume. vmcastillo@verizon.net

[Cr from Texas]

I'm not familiar with your model.
If it was a 123, I'd suspect the monovalve.