For the next guy/gal - Headers and melted wiring harness

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Ftera

Ftera

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Yellow, is that 20a?

Yes it is a 20a fuse. I'd carry an assortment just in case.

---------- Post added at 09:07 PM ---------- Previous post was at 08:51 PM ----------

Yellow, is that 20a?

Did they cover that under warranty being replacement headers, if they said that is what caused the issue?

They covered the 02 sensor under warranty. That was cool cause they coulda just said no way since i had ltb. No they did not take harness apart at all. just tucked it back in and said its good to go. Well, that wasnt the case but I do thank them for at least covering the 02 sensor. :)
 

Rookie

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That sucker is melted alright. When I initially had this happen the first time I took it in and they said it wasn't the harness even though I saw the same thing you did. Funny part was you could tell they had pulled all of the tape off of it and tried to put it back on. I'm still convinced they tried to repair it and didn't say anything because it would have blatantly been there fault.

Glad to see everything squared away.


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BeansGT

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I have to look but im wondering if there is a way to route the harness away from the headers . Thanks for the write up also .
 

bobcat82nd

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So i was out on a barstow to vegas run when en route there the check engine light came on? Mike S used his handy bluetooth obdII scanner and the code read p0133 (low voltage bank 1 02 sensor). Truck ran all the same so I ignored it. What else could I do.
Later on down the trail the check engine light went away. I was like ok.

Now coming back from vegas to barstow is when all hell broke loose. I initially got the check engine light but no difference felt driving.
At that point I had my locker engaged.
About a mile down the trail it happened. Tool icon lit up, hill decent fualt, service atrac and the truck went into limp mode.

Im still learning the ins and outs of these trucks so I called it a day and limped it home. That was not much fun. Good thing Jeff from SVC found me on the freeway, checked some things out but we could not figure it out so he escorted me as far down the 15 as he could. Thank you Jeff and SVC.

Went home and started reading all kinds of threads. Quickly I figured out to go check fuse #76 under the hood. Sure enough it was blown. Changed it out and truck ran fine with only the check engine light on and code p0133.

Took the truck to the dealer and they claimed it was a bad 02 sensor and they changed it under warranty even though I had lth. I pointed out to them that the harness was laying on my header but they said it was OK and sent me on my way. No not check engine light once I picked her up but I still knew something was not right. Something had sorted fuse #76 so I took her in to have the harness checked out.

Conclusion: The wiring harness was melted. The one that leads to the tranny and controls 4wd system, locker, 02 sensors and whatever else from the ecu passenger side. It was destroyed.

No fixing that one. So, I had a harness emergency mailed from Detroit and swapped out. Problem solved.

My suggestion to anyone running lth or not, is to check your harness and perhaps use extra ties and double heat shield wrap it. Its a weak link. Also, if this happens to you on the trail, 1st thing is check fuse #76 and replace fuse if burned out. Then check to see if your harness is contacting something hot like your headers. In a pinch move it and secure it. Dont use your locker or 4wd system as there is the possibility as was my case that by doing so and the wet conditions it shorted and that is why my fuse blew.

I hope this helps anyone that may experience something similar and what to look for to get out of a false limp mode a make it home in a better fashion than I did.

Good information! My CEL came on after a day in the desert and took the truck in today. Dealer states the codes are being thrown due to no read (non-existent) on both Cats. Everything was fine until recently. I have American Racing Long Tube headers and will need to do some searching down there tomorrow.
 
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