Engine cooling fams

I believe all cars have a cooling fan relay. Relays carry the load of the higher amps circuits of motors, headlights, etcetera. Radiator (engine) cooling fans come on when driving in hot weather when the vehicle is not moving fast enough to get air flow through the radiator. Cooling fans should always come on with the A/C and Defrost functions. (A/C makes more heat under the hood at the condenser.) I often use that as a quick test. If they don't come on, that's when I swap out the relay in the fuse box with a known good relay. You can also hook 12 volts directly to the fan to test run it. Polarity + and -- won't matter on a test.

Where are the cooling fan relays located on a 2000 Mercedes clk430? I can't find them. Also, how can I get a wiring diagram for the engine cooling fan and a.c. systems? Thank you, Tommy.

I won't be able to provide diagrams but if you look in your fuse panel you will see all the relays and labeling on the lid. For more detailed info, I always liked the Chilton manuals available at the auto parts store. Also, you may be able to Google more information. Sorry I can not help more but if it's not overheating, it's probably not broken.