Hi,
The AC in my 2002 MC does not start. When clicking on the button on the dash the green light does not light up, and the AC does not start. What can be the error?

The background is that a leaking wind screen caused a short circuit in the fuse box, making all electric functions in the car stop working. The garage has managed to get everything except the AC working again. The AC works when power is fed to it directly. The garage has tried to replace the button on the dash without success. The freon and pressure levels are OK. There are no fault codes and all electric wiring, fuses and relays seem to be OK. Anyone having an idea on where to look for the problem?

Appreciate all suggestions!

Regards,
Stefan Bergau
Stockholm, Sweden

 

I hope your problem is as simple and embarrassing as mine. I was smashing the AC button over and over again and it would NOT light up. After cursing and yelling for a few moments, I realized the fan was in the "off" position. After turning the fan on, the AC button worked again.

 

Unfortunatley the solution is not that easy. The fan is on, still no actions from the AC

 

Don't know if this is your case, but double check your 5A fuses under the hood (I think it's fuse F5... don't have my Bentley manual immediately handy). I had an issue where the fan worked but was blowing warm air, could hear the compressor kick on and was fully gassed, but every time you tried to engage the AC, that 5A fuse would blow, and without that fuse, you can't get AC.

Found that fuse was connected to the power steering fan (to cool the PS pump) under the front of the car. Search the forums for more info on that -- that fan is well known for getting dirt and gunk in it and seizing up hard. Mine was 100% locked up. Initially tried oiling it up with WD40 and got it spinning again, but not enough to prevent it from seizing and blowing the fuse, so I had to get a replacement from the dealership parts store (about $200 -- but they said the design was changed just recently to improve it from getting dirt in the gears).

Very easy to replace if you have jack stands. Just jacked up the front of the car, two bolts and a 3-pin electrical connector. Popped on the new fan, replaced the fuse, AC has worked great since.

Good luck!