So i've done a lot of reading and I'm still having a hard time telling whether my problem is due to the CCU or monovalve. I just took the Benz out for about 15 minutes and had full heat the entire time. I go from full heat on the dial to full cool and I don't notice any different in temp. ALso, if I go across the row from defrost to those other buttons to the right I notice NO difference. However, there is a difference b/w high and low fan. The difference in fan speed is the only differnence I notice out of all the buttons. Temp stays at full heat it seems.
I know my vacuum is shot in the cabin so that could explain why I'm not noticing a diffence b/w which pods are blowing air. Currently I get defrost and the pods against the doors blow. I bought a used CCU and that's what I'm using now.
Is this my monovalve failed and stuck open or is it my CCU?

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1983 300D TurboDiesel