AC temp dial trouble
 

Would anyone know why if I spun the temp wheel for the AC/HEAT to hot and turned it back the ac wont get cold again. 1986 W124 300 E that was cold and just had it checked told they know AC parts are all fine with enough freon as well. So is it this switch? Is there a way to turn it back cold manually?? All else works as should.

Thanks!

Probably a rip in the diaphragm on the monowater valve, there is a repair kit you can buy for it.

Tried finding the kit here. No go. Here is a link. You can inspect it first to make sure it's the problem:
http://www.thepartsbin.com/brands/bosch/bosch_mono_valve_repair_kit.html