Wiring meltdown

[Trucker73]

Hello all I need help figuring out what caused my 86 f250’s wiring harness to burn. Looks like it sarted from the red wire on top of the injection pump and burned like a fuse all the way under the dash. I now have no lights or any power. Thanks for your time and help. Possible link to find new harness. Thanks.

 

[Danielle]

Usually with situation in an older vehicle, I redo the harness so I can see if the issue can't be found because it was a rubbed through situation that melted away the evidence and cause.

But I also make sure once new harness is in place, before I make it pretty and put loom on or secure it anywhere, I do small tests of powering it to see if anything begins overheating and then I start eliminating things at the end of each circuit of harness

If you can't keep a meter with a beep on the suspect, having a friend feel for heat is the next best thing haha

But I go over it a lot, since dead customers can't pay. It's a tedious process and you may find more than one possible cause:

Previous owner hacked into this wire for power to radio

Previous owner hacked that wire for power to their cb

Previous owner hacked this wire for ground to their gauge

 

[Trucker73]

Thanks Danielle. The has never been tampered with but it started at the fuel shut off red wire and burned all the way to the harness under the dash. Just can’t figure why it burned at the injection pump. I’m not very good with automotive wiring that’s something that I need to learn.

 

[Trucker73]

Meant to say the truck has never been tampered with it’s all original never a problem but have noticed lately my lights pulsating.