it would not start. I took the starter and had it tested and it was fine?

I looked at a charger se. Did you check for voltage at the starter? Also check voltage and ground at starter relay? At the relay, terminal 85 is voltage for the coil side of relay, goes hot with the key in the crank position. Terminal 86 is ground for the coil side of relay, controlled by computer. Terminal 30, for load side of relay is hot all the time. When relay is energized that line with arrowhead moves to terminal 87, carries voltage to starter.

Just to add, any testing on the starter circuit, make sure the tranny is in park or neutral and the parking brake is set.