A 1984 Euro 240D was just given to me from my Dad. It has a 16 yr (give or take) aftermarket A/C system. He has had it for the past 11 years and has several A/C parts replaced. Most recently the compressor and Evaporator fan relay switch. It worked for several days, long enough for me to pick the car up in Charlotte and bring it to GA. Two days later I have no A/C. After doing some meter testing myself, I found the relay was hot to the touch. Further investigating tells me the shop in Charlotte wired the + wire from the battery and the switched + from the A/C unit were flip flopped. I checked all fuses and grounds, they are fine. When I check the switched + from the A/C unit there is no current to both the compressor and the evap fan Relays. I called a local car repair shop and they said that because it was wired wrong this would have drawn too many amps from the A/C unit therefore possibly burning something up. I have done meter tests on the dash A/C wheel switches and although they are complicated to follow, I have a reasonable assurance that the are working properly. The wiring harness under the dash goes to a circuit board which I pulled last night. The board has a small black box on it among other circuitry with DC 12V written on it. This box appears to be distorted a little which leads me to beleive it overheated. Am I on a wild goose chase or do you think I am on the right track. If so how in the world can I get a new circuit board for this aftermarket system??