I have a 1992 400E, can anyone tell me what the four relays are in the big sardine can on the passengers side by the firewall? One has blade fuses on top . I know one is for the ASR, and one is for the fuel injection (LH), but what are the other two?

The real reson I ask is my aux fans don't come on at all, even when the engine temp is close to 120c , and my a/c doesn't work. When I brought it to my repair shop they said the it was most likely the compressor control relay. Here's the problem; nobody seems to know where it is, including my tech. When I called a local mercedes dealership parts counter he couldn't find a part? Now I'm completely lost!