I have a 1985 190E with air conditioning that doesn't work. If I send power to compressor it works fine. I have checked the fuse and also tried disconnecting wire from water pump housing. I had system recharged and tested for leaks still to no avail. Someone mentioned about wires going to a red or green sensor by battery what does this do? Where is the relay located for ac and can the relay be checked to see if ok? Is there any other fuses besides one in fusebox? I am lost and very puzzled. If anyone can give me any help it would be greatly appreciated.