Electrical problem found

[WB72]

The last time I drove my truck in the night was about three years ago. I remember the lights just going off. Yes, I did panic, I got her stopped and was just about to start checking around, I smelt a plastic melting smell. Just as quick as they went off, the lights started working again.

Now three years later, I am triing to get this unit back on the road, I found a melted wire that is about a foot from the instrument cluster that goes to the rear parking lights. If I just replace the wiring, will I have the same heat problem again?

Also when I have the rear wiring unplugged, the signal lights in the front blink faster than when the rear is plugged in, is this normal? I have electronic flashers (both signal and hazzards)installed.

If I replace the wiring, could I just splice into the harness that is still OK and go to the rear and slpice again to the rear connectors?

[Lippyp]

The front lights will blink faster with no rears attached as there is less load on the flasher. It is also a useful signal to tell you you have a bulb out. I would suggest that it's probably time to re-wire the back end. I have similar problems and it's just down to 36 year old wiring going brittle and cracking and shorting out. I'm going to have to build a new rear loom from scratch to take into account the modifications made to make my truck legal in the UK and the trailer hitch wiring.

[WB72]

Would there be any problems if I used a larger wire to replace the old wire?

Any ideas on why the wire got hot?

[nightmare]

no, you won' t have any problems, but if you do just replace the wire, it would be better than using the originals. as far as why the wire got hot, could be any number of things, like an electrical power surge to the rear, wire was already weak in that spot, ie bent, crimped, etc. i'm sure that if it has never been replaced before, it was just due to old age.

[jhow66]

The wire got hot because there was a short to ground somewhere(a wire with power on it touched a bare metal surface). This has the same effect as a welder hence the melted wire. It should have blown a fuse before it did this. Check your fuse panel to see if someone has used alum. foil on a fuse or a solid piece of wire for a fuse. What color was the wire that melted?

[Stocker]

No need to go to a larger wire just to light a couple parking lamps, though it wouldn't hurt anything. I would temporarily splice in a length of wire with an in-line fuse just to check things out before making permanent repairs. Acually, it sounds as though the wire to the rear lamps got grounded, and that should be checked first. With the bulbs out, you should read no ground or voltage on the wire.

[WB72]

The wire was brown, it was melted between the dash and firewall (in the cab).

I think that it would be easy enough to rewire the rear harness.

How could I make the harness that goes from the dash to the rear of the truck?

Should I replace the wire completly or just close to where it goes to the instruments? I don't have the dash off, so I don't know where the other wires lead to.

[Lippyp]

You can buy a new rear harness from any of the vendors on the board and it's a plug and go job. The only reason I am making mine is that my lights have been adapted to be legal in the UK i.e My back-up lights are now turn signals with amber bulbs, I have a rear fog lamp mounted on my step bumper and a matching back-up light coming and a UK spec trailer socket. It works out to be easier (and cheaper) to make a new harness from scratch than import a new one and adapt it. If mine was standard I'd buy a new one like a shot as I have done for the engine.