My compressor is not turning on when ac is turned on. I had my car in a shop the other day for him to take a quick look at it and he jumpered one of the control wires that is behind the pass headlamps. Does anyone know what wires are which. The two wires on the coolant line have +12v on them. THere is a black wire hanging off the comp with +12 on it. Where is the switched ground at to make the compressor come on?