Help! Wiring Harness Smoking.

[Codychace]

Hello,
Bought a 2025 Lonestar 4x4 off-road back in Oct. The day before thanksgiving, I took it to the dealer because the battery was dying. They charged it throughout the day and it seemed fine. Thanksgiving day it didn’t start. Ended up having to get it towed. This time to a different dealer. This dealer found the main wiring harness to be burnt. So they replaced the generator and wiring harness. Started the truck, and the new wiring harness started smoking. The engineers now want to change the wiring harness again. Obviously this most likely won’t do anything. I’m now on around 45 days of it being in the shop. Will most likely be getting a lawyer. Has anyone else experienced this? Could it be a bad battery shorting and sending to much power to the wires?

 

[kapinallinen2]

Could it be a bad battery shorting and sending to much power to the wires?

No.
Everything is fused to the hilt or protected by the modules, not sure how that is even possible unless someone has altered something.
Any idea what "main" wiring harness they want to replace?

 

[Codychace]

No.
Everything is fused to the hilt or protected by the modules, not sure how that is even possible unless someone has altered something.
Any idea what "main" wiring harness they want to replace?

Main powertrain harness. They’ve already replaced it once.

 

[DEG]

If wires in a bundle are burning there likely is a short to ground in a wire segment that is not protected by a fuse. If it were protected by a fuse, the wires would not be burning. It's probably a single wire getting hot enough to burn the surrounding wires. If they have changed the bundle once then the short is likely located outside of the bundle so changing the bundle again will not solve the problem. This could be difficult to diagnose since the main power harness directly or indirectly feeds almost every system in the truck, but a good electrician should be able to isolate the issue. However, good electricians are rare.

 

[HSKR R/T]

Before getting a lawyer, talk to dealer management, and ask about a buy back, or getting you into a new truck, straight across.

 

[kapinallinen2]

I plugged in "main powertrain harness" in alldatadiy, comes back with 182 hits.
Would be interesting to know what functionality this "main harness" serves/connects to.
Maybe the second or third time is a charm and the component causing the overload condition will manifest itself!

 

[kapinallinen2]

If wires in a bundle are burning there likely is a short to ground in a wire segment that is not protected by a fuse. If it were protected by a fuse, the wires would not be burning. It's probably a single wire getting hot enough to burn the surrounding wires. If they have changed the bundle once then the short is likely located outside of the bundle so changing the bundle again will not solve the problem. This could be difficult to diagnose since the main power harness directly or indirectly feeds almost every system in the truck, but a good electrician should be able to isolate the issue. However, good electricians are rare.

Sorry to say but an electrician would not stand a chance in hell diagnosing these vehicles.

 

[Codychace]

If wires in a bundle are burning there likely is a short to ground in a wire segment that is not protected by a fuse. If it were protected by a fuse, the wires would not be burning. It's probably a single wire getting hot enough to burn the surrounding wires. If they have changed the bundle once then the short is likely located outside of the bundle so changing the bundle again will not solve the problem. This could be difficult to diagnose since the main power harness directly or indirectly feeds almost every system in the truck, but a good electrician should be able to isolate the issue. However, good electricians are rare.

Right, which is what sucks because they are changing it again. It’s most likely not going to fix the problem. So sounds like I won’t be getting my truck back anytime soon. Im on day like 45 or 46.

 

[Codychace]

Before getting a lawyer, talk to dealer management, and ask about a buy back, or getting you into a new truck, straight across.

I might try this, but will probably tell them my next step is finding a lawyer. My wife and I have to have to two vehicles at this point.

 

[Codychace]

I plugged in "main powertrain harness" in alldatadiy, comes back with 182 hits.
Would be interesting to know what functionality this "main harness" serves/connects to.
Maybe the second or third time is a charm and the component causing the overload condition will manifest itself!

Really? I’ll search again. I didn’t find anything related to what I’m asking.

 

[Codychace]

Sorry to say but an electrician would not stand a chance in hell diagnosing these vehicles.

I think I agree with you. However, they should be able to follow some diagrams. It is a lot though.

 

[kapinallinen2]

There are six pages of these alone. They all terminate to 30 or so common grounding points so not all that bad over all.

 

[Mountain Whiskey]

Have them put the smoke back in the wire. It will be fine then.

 

[HemiDude]

Have them put the smoke back in the wire. It will be fine then.

Ahhh, the good ole days. We used to use that joke often when I worked in the shops. I made that comment fairly recently to an electrician out in one of our bays, he had no idea what I was talking about.