climate control troubleshooting
 

Ok so in my girlfriend's 300CD and in my 300SDL when off the climate control will Kick on randomly.. Sometimes it will stay on some times it will turn off after a few seconds.

both have gotten much worse over time. Hers has gotten to the point where it rarely works unless it decides to turn itself on breifly, Mine has shown these symptom for a while, but is getting to the point where it happens quite frequently, as in every five mins of driving....

Anyone ever had this happen to them?

How'd you fix it?

It may be a failing CCU, you may want to pull it and check for cold solders, if you find any, re-flow the solder, adding some if necessary.

The search feature works wonders. Lots of information on this subject.
However look at this..................
http://w123maintenance.blogspot.com/2007/10/automatic-climate-control-unit-repair.html

x2

also checkout the kilma relay out too

I had the same problem with an 84 300D's CCU. It's probably a failing CCU unit. I'd try to re-flow it, as others have stated, adding solder where needed. If that doesn't work, you might want to look into a rebuilt / remanufactured unit off Ebay - one can be had for under $300.

Once you get it working, I'd also highly suggest putting a 1A fuse in-line with the auxiliary water pump. When those things blow, they have a nasty tendency of taking the CCU out with it.