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Discussion Starter · #1 ·
Hello! I'm in the process of an LS swap. I started with the stock 4.0L 42RE auto and have installed a 2005 5.3L / 4l60E using many parts from Novak Industries for the swap. I intend to keep the Jeep wiring harness to retain factory gauges/controls along with the re-worked (by Novak) GM harness to run the LS. I pulled the Jeep harness out and removed from it the following circuits to clean it up:

1) O2 sensors
2) Coils
3) Injectors
4) Transmission controls

I have the new motor / tranny (adapted to the original np241 t-case) installed now. and I have both the jeep and GM harness re-installed and connected. I have the battery grounded to the frame, frame to engine, engine to body at original firewall location as well as the firewall to hood factory grounds and have validated continuity between them all. There is also a small ground coming from the cabin through the firewall at the passenger side under the battery tray I have grounded to the frame.

Problem is though, when I connected the battery and turned on the ignition, I have NO POWER inside the Jeep. Everything worked properly before I removed the engine/harness. I am leaning towards a missing ground to the PCM, but I'm not sure how the PCM is grounded / powered?

Anyone who might be able to help nudge me in the right direction to troubleshoot this?

Thanks!
-Todd
 

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maybe a 06TJ wiring diagram, a OEM manual should have that...
You are running a GM pcm? and that diagram will also be needed.

after rereading - you say nothing works - headlights, wipers, brake lights, horn?

The gauges would likely not work with a GM PCM.

anyway diagrams are suggested. I see pulling hair out - banging head, cursing are in your future -
 

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Discussion Starter · #3 ·
maybe a 06TJ wiring diagram, a OEM manual should have that...
You are running a GM pcm? and that diagram will also be needed.

after rereading - you say nothing works - headlights, wipers, brake lights, horn?

The gauges would likely not work with a GM PCM.

anyway diagrams are suggested. I see pulling hair out - banging head, cursing are in your future -
LOL - yeah - there will be much wailing and gnashing of teeth for the forseeable future...

I do have the Jeep wiring diagrams and I'm cataloging all the in-engine bay plugs/wires/grounds to verify them all at the jeep.

The gauges will be running off a Novak emulator for the tach, temp and oil pressure from the original jeep sensors mounted on the LS enginge. Speedo VSS will come from the GM harness.

Your note sparked a thought - the wipers DID work when I first connected it...so I got to checking and one of the plugs by the drivers side kick-panel was not completely connected...I connected that and now have power to the interior (instrument, radio, lights, etc).

Powered up the GM computer and lo-an-behold, it's cranking! I'll prime and re-connect the injectors and coils and just maybe she will fire.
 
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