1986 300SDL: Cimate Control Unit
 

Hey guys. My climate control unit used to work fine. Push a button, it worked. Nowadays nothing happens until it seems to warm up. I already replaced fuses and I don't believe it's the blower motor (replaced last year). The recirculator button's light doesn't light when any of the control unit's buttons are engaged. Once the unit warms up and the blower kicks on does the recirculator light come on. Hence I believe it's the control unit itself that's faulty. The defrost button doesn't even do anything. I've already taken the unit out and resoldered the connections on the main board but that didn't change things. No visible burnt marks anywhere on the main circuit board. BTW, when it does finally kick on if I have hit any buttons before it kicked on the ccu appears to remember what buttons I hit and goes thru them all before stopping at the last button press. (if that doesn't confuse you :) ) Any help would be really appreciated.
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Tony

Two, possibly three, capacitors on the CCU circuit board were leaking. I desoldered them, cleaned the board with iso alcohol and put new caps in. I've got to wait for some epoxy on a broken plastic part to dry, then she's going back in for testing.

Look around for a good reman, Programma or Beckmann Technologies does this for those units. I have seen them pop up in junkyards often (two of mine came from there for a real expensive $10 each)

You need an '86-91. '85 and older will not work.