electronics question - PeachParts Mercedes-Benz Forum

omne207 · #1 10-06-2007, 12:49 AM

i have an issue with my climate control computer. i am wondering if maybe the short witch i believe to be the problem may be in the air conditioning switch or maybe perhaps the thermostat dial. i was wondering if perhaps anyone would be familiar with the electronics in this devise. my benzo is a 79 300d. the only reason why i think it could be these two is because the switch to turn on the air conditioning does not work could be freon i realize and the dial does not change the temp of the air. also i believe i have unplugged the wires to the control panel from the heater control pump i believe it is the wire to that since i no longer have any heat except defroster. i had to unplug it due to the fact this part stayed on while the car was not running and would get really hot due to this malfunction i was told it wouldnt hurt the car by a mechanic who i was ordering parts from

jkoebel · #2 10-06-2007, 01:18 AM

All I know is the vacuum-actuated automatic CCU is a big point of failure.

GDL refurb's the control modules, but you've also got things like the monovalve, all the vacuum parts, etc. that can screw up.

omne207 · #3 10-06-2007, 04:32 AM

are they seperate from the vacuum pump it sound like a dumb question but i just replaced that and if it may have had a hand in fixing that it would be great

jkoebel · #4 10-06-2007, 07:35 AM

Yes, all separate from the vacuum pump, although a lot of them are connected to it.

Replacing the vac pump if its marginal is only a good thing, but the climate controls themselves have about a half-dozen spots to leak all buried deep within your dash. Try plugging the wires going to the CCU inside the engine bay (they'll be near your power locks, I think it's a green wire? Not the one for the ignition, though.)

omne207 · #5 10-06-2007, 12:52 PM

cool thank you i am working all the little kinks out my car for now i dont really think the previous owner cared so much about it