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Old Aug 31, 2010 | 11:37 PM
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Default wiring help!

Vehicle is a 94' Imp-SS, engine is 04' 5.3. I had a guy(Ebay seller) to rework both the 5.3 harness and my original LT1 harness so that this would be a plug n play swap, but I've run into some wiring headaches and I can't get this guy to respond so I'm hoping you guy's can assist. Here we go.....
Theres a wire on the lt1 harness labeled fuel pump (+), and then there is another green wire on the lt1 harness labeled fuel pump, however on the 5.3 harness there is only one wire labeled fuel pump with no polarity marking.



Next is a wire on the lt1 harness labeled a/c request but there is no corresponding a/c request wire in the 5.3 harness, but both harnesses do have wires labeled a/c clutch.



Next there is a wire on the lt1 harness labeled switched 12volts but there is no corresponding wire on the 5.3 harness.



Next there are two wires on the lt1 harness labeled injector but there is only one wire on the 5.3 harness labeled injector.



Last but not least, I'm not sure which "big wire" goes to the alternator. Does it go to the stud on the back of the alternator and should I install a resistor in this line to keep from burning the alternator up?



I realize these are quit a few questions but I'm wrestling with this project on my own and trying to get it done, I really do appreciate you guy's time and help.
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Old Sep 1, 2010 | 12:04 AM
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Fuel pump needs a relay to control it. The output from the PCM is negative trigger.

There will be two orange wires that are batt + at all times. Keyed power wires are all pink.

You shouldn't need a resister in line with the alternator, not sure where that came from. There will be a plug that controls the alternator from the PCM (typically brown wire) and a second (larger) wire going to the battery or starter from the charge side of the alternator.

That's enough from memory at midnight...

Probably the most concise and accurate place I have seen for wiring harness information is LT1Swap.com. Dig through that, most of it is quite self explanatory. You are fortunate, I didn't know about it or many other sites when I did my first swap.
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Old Sep 1, 2010 | 12:09 AM
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Thanks man, and yeah I've checked that website b4 but I'm not good at reading wiring diagrams which is why I opted to have these harnesses dummy proofed but it looks like i got screwed on this deal. I shouldve known when it took the guy over 6 mos to get my harnesses back to me that something wasnt right.
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Old Sep 1, 2010 | 04:19 AM
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Isn't the fuel pump positive triggered from the pcm? It is on ever harness I have re-worked.
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Old Sep 1, 2010 | 11:48 AM
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Originally Posted by LS1MCSS
Isn't the fuel pump positive triggered from the pcm? It is on ever harness I have re-worked.
Yes fuel pump is positive trigger from PCM
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Old Sep 1, 2010 | 06:52 PM
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From: KCMO
Default Dammit!

Originally Posted by LS1MCSS
Isn't the fuel pump positive triggered from the pcm? It is on ever harness I have re-worked.
Hey, I said it was midnight didn't I? You're right, positive trigger on that one. Dammit, this makes two mistakes for the year - and I was doing so well! Grrr! J/K

Things like the check engine light are negative trigger (i.e. you supply 12 volts and it grounds through the PCM).
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Old Sep 1, 2010 | 09:01 PM
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Check your PM's.
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