Did this mod to my car last week after I saw this post. :devfu: Except my ground wire was the black wire?? How to test:- Simply remove plug from solenoid and put the (-) wire of a multimeter on a ground point of the chassis, start the car and test the plug from harness to see which wire has +12V from ECU with (+) wire of multimeter. Once found switch off motor and cut the other wire (which is the ground wire switched by ECU) ON THE SOLENOID SIDE OF THE PLUG and add wire to ground it on chassis. Solder and Insulate bare wires, hook up plug again and enjoy more boost. I also resetted ECU after this and have had no problems. Thinking of adding a switch inside on dash so I can set it so constant power not on solenoid on those long trips between states, might help solenoid from burning out??