I just finished my converter swap and truck runs great except when the headlights come on... then it kicks on my fans, trips some codes and reduces power. I can cut off the headlights, clear the codes and it's back to normal... I pulled the relays for the fans and they look ok so IDEAS????

 

what are the codes

 

This happened right after the converter swap? I'd check all of the wiring and make sure that nothing is pinched, particularly between the engine and trans.

 

tripping codes...
120 tps sensor switch a
220 tps sensor switch b
1516 my reader doesn't list this

I have unhooked the pcm lead and power for the fans.. didn't help

When the ignition is turned on all 4 headlights come on and the truck runs great until I turn on the lights or the ac comes on... I haven't tried to undo the a/c lead for the fans yet.. HELP I have to work tomorrow night need lights

 

P1516=Intake Manifold Runner Control Error (Bank 1)...is there any possibility that the harness is pinched and shorted from the converter install????

 

but with a pinched wire the problem should occur all the time not just with the headlights and fan right??

 

fans are totaly disconnected and the problem still occurs.... It only does it when the headlights are turned on. The running lights don't trip it only the headlights and all 4 come on. I need this ASAP

 

If I pull the realays for the headlamps it still happens but I can turn them off clear the codes and it's normal again. But If I pull the fuses by the relays, leave the relays in then it still happens and won't kick out of REP mode, even when I clear the codes it immediately limps again with headlights off. WHAT GIVES???

 

Not necessarily, if two wires are shorted to each other, and you turn something on and provide power or ground to one of those wires, it will affect the other wire. Since this problem occured immediately after the transmission was removed, it makes me think you should go back and look at everything involved with that repair. It sounds like you have a short somewhere, unless there is a bad ground and turning the headlights on causes some sort of feedback? I'd visually inspect the harness, especially on the left side of the engine since you're getting codes for the left bank and TPS, which are on the left side.

 

I will look again in the morning but there really isn't any wires that run between the motor and trans there that could have been messed up. Also found out today it does it when the a/c kicks on.... I know it is a short, checked all fuses in the cab and underhood. If I can't figure it out in the morning it's off to the dealership at $79.95 an hour