Mechanic did not remove the module on install.Wired up for 4 pin and I made sure module was removed.Car idled fine and would not turn off when ignition is in off position.Wired the diode in and problems solved.Whom so ever purchase a 6a box for gm hei 4 pin module.Make sure you order pn 8860.Your going to need it.I was lucky the local speed shop had the part in stock.