on a '90 TE the aux. fans turn on when I turn on the car. After about 5 minutes they'll turn off. Sometimes they'll turn themselfs on for no reason (ie. the car is totally cool) The other day I turned on the car and opened the hood. As usual the aux. fans turned on and after about a minute they started to surge. They would turn on, then off, then on again ect. While they were doing that, I heard lots of rapid clicking comming from the relay box behind the fuses. The clicking was in sync with the powering on and off of the fans. This leads me to beleive that I have a relay problem. Can anybody tell me which relay controls those aux fans? There is a bright green one and a black square one towards the front of the relay compartment - one of which I believe is the culprit.

Thanks a bunch

You don't have a relay problem, but rather a sensor problem.

In most cases, the blue thermal sensor on the cylinder head needs to be replaced.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS