Last week my 2000 ML320 had a service done at the dealership where they change the wiring harness for the auxiliary cooling fans. Their claim was the fuse was blown for the aux. fans. I had never had a problem with the fans before that. However I remember those fans starting up for a few seconds at different speeds after starting the engine with or without the A/C. After this replacement they start (high speed only) and only when the A/C is on. I check them with the engine hot (92-93 Celsius measured at the thermostat housing) and they do not start unless you put the A/C on. I don't think this is normal. What I think is they just mess-up the wiring when they connected the new harness or maybe the new harness is not compatible. The car has only 16.000 mi. and the vin number is A 176951 where they shouldn't have replaced the harness. Can anybody help me to put back the original harness which is still there or to fix the new one.
I will post some pictures with their work in this afternoon.
Thank you for your help.

Check this thread, it might answer your questions

http://www.peachparts.com/shopforum/showthread.php?threadid=91035