From what I remember it should use a lock-up relay that is controlled by the PCM. That way the PCM know when its in 3rd gear and know the eng temp , TPS volts , vehicle speed and MAP volts to determine when to apply the lock-up. You can leave it unhooked and it just wont have the lock-up. On that year it will set a code but should not turn on the Ck Eng lite. Or you can use the lock-up which is a good idea for cruising as I believe there are some aftermarket kits around that will apply the lock-up by speed along with eng vac and temp. I dont know if the aftermarket kit will monitor TPS. Maybe someone will chime in who knows what company makes the kits, Ron