560sl Air conditioner blowing Hot air
 

My 1987 560sl air conditioner will randomly blow HOT air. The air conditioner will start out working properly...When I shut the car off & then return to restart it, the air conditioner will blow HOT air instead of Cold air.. The compressor has recently been replaced & refilled with the proper coolant. Somethimes it will blow the cold air & then it will suddenly start blowing hot air. Does anyone have any ideas what could be causing this problem? THANKS

Start by checking Klima relay and the monovalve.

Jim

I think various Mercs (I have a 560 SEC) have a sort-of default setting where if the monovalve/duovalve fails to work properly, the system blows hot air whatever you do to the control settings (and on my car the recirc switch telltale light flashes). Apparently it's so that you can at least limp home with windscreen demisted!

I could find nothing about this in the handbook or workshop manual, but I eventually tracked down a tech article on the internet. Unfortunately I can't now trace it. But check the monovalve/duovalve anyway: there are forum posts about this problem - apparently they sometimes stick.

Good luck!

I too hate that when it happens.....I usually get out and wiggle the fuse and all is ok (No.7)