I would pitch the thing in the garbage to avoid the headache you'll get from the damn light blinking back and forth all the time except at WOT when you hook it up right.
But try getting a good clean ground(sharing grounds with components you are drawing power or signal from is a good idea). Also make sure it is good power, I see so many people just tapping fuses and I think that is an awful idea. Get power from your ignition harness or battery and don't forget the fuse. One big tip is make good quality connections, I use tape and soder everytime, but then I am anal and have brainwashed into doing that after three years of mobile electronics install...
Good luck.