Where is the coolant relay located at in a 2002 s500

SOURCE: we have benz s500 2006. looking for coolan fan

First of all, I don't mean to be a pain, but why are you wanting to "fit" the relay? If you don't know where it is, you could not possibly have tested it. If you have not tested it, then you cannot know with any certainty that replacing the relay will fix whatever problem you are trying to repair. There are a lot of other possible causes if you are trying to fix a cooling fan that won't work.

Please take a few moments to read this article: What Else Could Be Wrong?

With all that said, The relay that controlls your fan motor is the "Circuit 15 Relay". It is located in the Driver's Side SAM Module. It is marked "N" in the picture below.