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My buddy has an ‘04 LLY.

He’s had on ongoing issue for over a year now with his injector wiring.  He’s done the “ice pick” fix, and replaced the wiring and connectors multiple times but it’s always the same issue coming back a month or two later..

is there a fool proof fix for this?  Aftermarket wiring harness available that can stop this insanity once and for all?


I never had this issue when we had our LLY and I’d like to help him out if I can.

I know there’s several threads on here but they all seem to center around the ice pick fix.


Thanks guys...

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What codes are being set?


Theres several rub spots on an lly truck. Ones that comes to mind is by alternator and then by steering shaft. 

If your codes can narrow down which side it’s coming from, you can chase entire harness out fairly easily. 

I have also replaced an entire engine harness. Once. Won’t willingly do that one again. 

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Ok...here’s what I got from him today... (notice he calls it tractor mode, as in farm tractor).


It’s throwing #1 injector control circuit the. 7,6,4 injector circuit. Before it was the 1 and 6 losing connection at the injured plug replace those and 1 and 8 ice picked the rest lasted a few months now.. same codes I replaced all the plugs  it keeps losing connection at the butt connection so wires to short to soldier so I ran new wires same gauge soldered to the right bank does the same thing starts up then yes I think it shorting out the brown wire over by the alternator insulated them all in the control circuit now except for #7 I’m going to run a new loom to that injector bypassing the short by the alternator. But I’m starting to think it doesn’t like my new wires..I soldered them good and double shrink wrapped though I might unplug it from the ecim and clean. Before I soldered I hand twisted number 4 and 6 pigtails on and it ran good so I bit butt connectors and it went into tractor mode then I soldered them same thing it runs but if u touch the brown ground wire it goes into tractor mode it will run fine then tractor mode when started again..

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Check the connection at the bail connectors on top of engine driver side. Get it running and start pulling wires (gently). It’ll tear it’s head. 

What did the rest of the wires look like by the brown wire?  I’ve known them to break internally at that spot. Not that many though. 

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  • 3 weeks later...

Ok...my buddy fixed the brown wire, and replaced the entire injector harness for the 3rd time (this time he went with a factory injector harness instead of a knock-off).

Truck STILL throws codes for injectors 1, 4, 6, 7 control circuit open.


My thought (and I told him this a whole back) is he has a bad ficm. 
But he’s leaning more toward a bad male prong on 1 injector.🤷🏻‍♂️

Question for marksmith...is there a way to test the ficm?

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  • 2 weeks later...

Heard back from my buddy a couple of days ago.

after changing the harness twice and new injectors, his issues continued .

i bet him his ficm was bad because the problem would seem like it was fixed then after the truck warmed up it would come right back.  He changed out the ficm and now...PROBLEM SOLVED!


thanks to all of you for your help!

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