2004 Jeep TJ Wiring Harness Questions

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Geeknahalf

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Original poster
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May 20, 2022
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Hawaii
Hi Folks,

I have gotten to the point where I am contacting companies to make me wiring harnesses for my 2004 jeep TJ. My question is, how do I determine the correct engine harness part number I need to provide to the companies as a reference.

I have searched the internet, and many forums to include this one, for this answer with no luck. I have looked at the FSM as well but still unable to 100% determine what part number I need.

Any help would be greatly appreciated

Thanks in advance.

RS
 
I don't think I've ever seen a definitive list of TJ wire harness part numbers. I'm guessing each sub harness has a part number. None of it is documented in the VIN decoders. Guessing you will need to send in your existing harness.

-Mac
 
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macleanflood said:
I don't think I've ever seen a definitive list of TJ wire harness part numbers. I'm guessing each sub harness has a part number. None of it is documented in the VIN decoders. Guessing you will need to send in your existing harness.

-Mac
Click to expand...

God I hope not, current harness is not 100% wired correctly, where grounds and possible other parts are concerned, and I don't want them duplicating the issues. Still waiting to hear back form them, maybe they'll be able to read FSM and build from that..
Thx for response!

RS
 
Honestly I tried to repair what I have, however, it still doesn't pass the jiggle test. I jiggle the harness section above the valve cover and it will shut off. And every time I think I have it narrowed down or fixed I find out I'm wrong. I am also going to replace the harness that the engine harness connects to, the one with the 3 large connectors above the valve cover because if I press on that, (sometimes) it will shut off as well... Some times I don't have to do anything at all and it wont start until I jiggle the wiring harness... Tired of chasing ghosts and guessing I did things right..
 
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Would help a little if we knew the year and engine.

Fixing wiring is a pain. I'd deloom the entire engine harness and verify continuity and check ohms from pin to pin... usually starting at the PCM and going out.

-Mac
 
I’ve done that. Had the entire engine harness deloomed and spread out across my deck. Checked continuity on all connectors and verified as best I could all wires are correct according to the FSM. Still the issues persists. Additionally if I hook up the body ground to the eng. I get O2 heater low voltage error on all 4 O2 sensors and then the engine will shut off. Unhook Body ground, clear adaptive mem and it starts and runs. Previous owner did some hacking on wiring and I’ve never been able to figure it out.

Gotten to the point I’m tired of troubleshooting.

2004 wrangler 4.0
 
Ugh, that's terrible. I'd start by looking behind the dash, especially above the glove box and over on the drivers side for bad grounds or ignition wiring hacks.
 
Geeknahalf said:
Hi Folks,

I have gotten to the point where I am contacting companies to make me wiring harnesses for my 2004 jeep TJ. My question is, how do I determine the correct engine harness part number I need to provide to the companies as a reference.

I have searched the internet, and many forums to include this one, for this answer with no luck. I have looked at the FSM as well but still unable to 100% determine what part number I need.

Any help would be greatly appreciated

Thanks in advance.

RS
Click to expand...

‘04 Auto

https://www.ebay.com/itm/1367844171...pid=5337789113&customid=&toolid=10001&mkevt=1

‘04 Manual

https://www.ebay.com/itm/1367844194...pid=5337789113&customid=&toolid=10001&mkevt=1
 
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GoldenGorilla said:
Ugh, that's terrible. I'd start by looking behind the dash, especially above the glove box and over on the drivers side for bad grounds or ignition wiring hacks.
Click to expand...

I've been under the dash a few times and there's a single aftermarket wire coming from the fuse box going to some where, forgot where, but I disconnected it and no effect; problem still persists. Most of the splicing and dicing of the harness happened under the hood as far as I can tell, don't see any under the dash or in the steering column, except for the afore mentioned wire. I will revisit that wire though, now that you reminded me it's there...
 
Geeknahalf said:
I've been under the dash a few times and there's a single aftermarket wire coming from the fuse box going to some where, forgot where, but I disconnected it and no effect; problem still persists. Most of the splicing and dicing of the harness happened under the hood as far as I can tell, don't see any under the dash or in the steering column, except for the afore mentioned wire. I will revisit that wire though, now that you reminded me it's there...
Click to expand...

You can get a full engine harness at one of the links I gave above. No reason to have someone build one from scratch. They are available.
 
Geeknahalf said:
I looked at the one w auto trans, they don't ship to Hawaii :(
Thx for the effort of looking them up though, I do appreciate it.
Click to expand...

There are several for auto on eBay. Didn’t check shipping constraints on each one. I might be flying to Hawaii this year. Not sure what your timetable is for getting it fixed.
 
JMT said:
‘04 Auto

https://www.ebay.com/itm/1367844171...pid=5337789113&customid=&toolid=10001&mkevt=1

‘04 Manual

https://www.ebay.com/itm/1367844194...pid=5337789113&customid=&toolid=10001&mkevt=1
Click to expand...

I've looked at the one for the auto trans, they don't ship to Hawaii. :(

I am still looking for a used one though, in the best shape I can find. I am trying to look for ones that ship to Hawaii and, don't have any bald spots. Bald spots being parts of the harness where the factory loom is missing, replaced, or highly damaged. To me, this could be trouble spots where someone has been inside the harness or, could also be just my paranoia kicking in.

I really enjoy my jeep, just not this part of it..
 
JMT said:
There are several for auto on eBay. Didn’t check shipping constraints on each one. I might be flying to Hawaii this year. Not sure what your timetable is for getting it fixed.
Click to expand...

That is one hell of a thread there in your signature link, I don't ever recall seeing a post with 402 pages! It's like a novel :)
I will definitely read through that one. From the little I've read so far there's a lot of good information and links.

If you get out to Hawaii let me know. Not sure if you've ever been here before. If not, I would be more than happy to recommend places to visit, eat, and the like.

I've looked on eBay before, and purchased one. Unfortunately, it didn't work out for the better. Also, it's hard to find ones that accept returns as well. Seems no part of fixing this has been easy really, and it's quite discouraging.

On the upside, it's not my daily driver anymore so the timeframe is not critical. Plus I can still drive it, which I do on the weekends.
 
Usually it's blown capacitors. Also the 2005-06s had endemic PCM issues with the auto...the transmission controller was embedded into the PCM and would cook.

-Mac
 
Have you looked at Car-Part.com ? It searches junk yards. Find a yard that has the harness and contact them to see if they will ship to Hawaii.
 
macleanflood said:
Usually it's blown capacitors. Also the 2005-06s had endemic PCM issues with the auto...the transmission controller was embedded into the PCM and would cook.

-Mac
Click to expand...

Is the pcm able to be opened without damaging it? If so I’ll definitely take a look.
Mine has separate TCM, I already had to replace that one.
 

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