It sounds like the pressure valve you used was bad, and the compressor built up pressure until something let go.
The ecu is what turns on the fans, bypassing the things you did and installing a switch eliminated all the safeties you would have had. I am not sure about the dealer issue, i would suggest checking part numbers on the ecu, and running that against your options, if that is really the issue, then buy a cheap ecu with the right options and put it in, hoping you didnt destroy the system with what ever popped.