mars 10 remote start problem

I installed a Mars 10 remote start into my Pontiac Grand Prix GTP and I come up with a couple problems, I can't seem to find the wire to activate for the factory remote. I had it hooked up to the lock motor wire which is a gray wire that rests on negetive but sends a positive pulse when I hit the lock button on the remote. I used a relay to reverse the polarity to a negitive pulse, but when I try to remote start I get 3 clicks from the brain and no start.I'm using the tachless method, I don't know if the tach mode would make any difference. Any help please.

Thank You