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Help... electrical issue

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Old 03-22-2009, 07:22 PM
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Default Help... electrical issue

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????
Old 03-22-2009, 07:24 PM
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what are the codes
Old 03-22-2009, 07:42 PM
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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.
Old 03-22-2009, 09:05 PM
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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
Old 03-22-2009, 09:17 PM
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P1516=Intake Manifold Runner Control Error (Bank 1)...is there any possibility that the harness is pinched and shorted from the converter install????
Old 03-22-2009, 10:48 PM
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but with a pinched wire the problem should occur all the time not just with the headlights and fan right??
Old 03-23-2009, 08:45 AM
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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
Old 03-23-2009, 09:38 AM
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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???
Old 03-23-2009, 11:16 AM
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Originally Posted by fastgmc53
but with a pinched wire the problem should occur all the time not just with the headlights and fan right??
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.
Old 03-23-2009, 11:33 AM
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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


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