1995 E420 100,000 Climate control problem.

[nestorb98]

Thanks in advance for your valuable inputs...

I bought this E420 a few months back and have been slowly putting it back together. Yesterday I began tackling the climate control which has not worked at all. I removed the control unit and found a two square inch portion of the circuit board completely burned. I happened to have a spare unit but before installing it, I read that if the Monovalve if faulty that the over heating in that unit could cause the same circuit burn to be repeated.

This car runs, stops and handles great! And there is no visible cracking on the wiring harness...but it does have some electrical gremlins, for example fuse "C" which controls the power antenna, door lights, locking system and a few other circuits blows any fuse I try to put in there. I disconnected everything that is tied in to that fuse and it still blew a new fuse the instant I connected it.

So now that I found the burned circuit board and knowing that '95s where a bit "electrically challenged" and before I need psychiatric help...where should I begin?

[anziani]

I would begin by having someone read the codes. If you track down Jim Forgione"s web site, he gives instructions for making a simple LED reader. I think mine cost a whopping $10.
It is easy to use so at least you have an idea where the problem is. Far better than guessing and throwing parts at it.
Also contact "S Class Eddie" in Boston. Great guy for used 140 parts.
Anziani
'97 CL600 56K

[Zulfiqar]

Originally Posted by nestorb98

Thanks in advance for your valuable inputs...

I bought this E420 a few months back and have been slowly putting it back together. Yesterday I began tackling the climate control which has not worked at all. I removed the control unit and found a two square inch portion of the circuit board completely burned. I happened to have a spare unit but before installing it, I read that if the Monovalve if faulty that the over heating in that unit could cause the same circuit burn to be repeated.

This car runs, stops and handles great! And there is no visible cracking on the wiring harness...but it does have some electrical gremlins, for example fuse "C" which controls the power antenna, door lights, locking system and a few other circuits blows any fuse I try to put in there. I disconnected everything that is tied in to that fuse and it still blew a new fuse the instant I connected it.

So now that I found the burned circuit board and knowing that '95s where a bit "electrically challenged" and before I need psychiatric help...where should I begin?

my car had the power antenna fuse blown when I bought it, the culprit was a bad control box on the antenna itself. to find the short use a bulb on the load side of the fuse holder, disconnect everything on that load side and then look at the bulb, if its lit the wiring is shorted, find it.

[Larry Delor]

The blower motor resistor is also known to fail. It is pretty much under the windshield wiper. There are two versions, and it is usually the more expensive one that needs replacing (Murphy's law).

[DRICHFL]

Check your wires that runs on the driver side rear seat to the trunk... they maybe damage. The wires also runs into the trunk's deck lid. As you open & close the trunk lid the wires are stretch & can break.