My '95 C280 runs very hot while in traffic. The fans still come on but only briefly and not enough to bring temperatures back down to normal. Once out of traffic, the temperatures drop back to normal. Temps are about 79*C while driving and over 110*C while sitting in traffic. I've already replaced the temp. switch on top of the t-stat housing but the problem is still there. If I jump the fan switch, the temperature stays cool but the fan constantly runs. Anyone have any ideas or solutions?

Go check the aux fan fuse at top off the aux fan relay in side your fuse box,you have to remove fuse box cover use screw driver,relay is green color with blue fuse(15amps)at top.
hope this help. :)

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MB STARS Master Guild Technician,12 years MB tech
6 years independent shop owner

If the fuse that Stars talked about is blown, replace it with a 20A.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I would like to thank to both, MB STARS and BENZMAC, for their help. You were both correct, my fuse on the fan relay was blown.
I have replaced it with new one of 15 Amps for now, but I will put a 20 Amps ASAP.
One more time many thanks for saving me a lot of time and money. The MB dealer was going to charge me around $ 70 , just to talk to me.
They woul not tell me anything unles I took it to them for diagnosys. THANK YOU !!!
Keep up the good work! :D