So I let the factory smoke out of my wire harness

[antFJ]

if he replaced the whole front end harness with a "new" one that short would be on the old harness - on my 78 there are only two sections of the harness

- the one that has all wires for the dash and engine compartment
- the chassis and rear harness

(not counting wipers etc.)

right?

 

[Pin_Head]

Maybe, maybe not. It is very rare for a short to originate in the harness itself in my experience.

 

[ken_79-fj40]

The wire is burned from about 12 inches away from the fuse box all the way to the connection for the harness at the positive terminal on the battery. It's hard to tell but it looks like the wire just grounded out under the dash somewhere. I can't think of any other explanation considering the truck was in the garage with the ignition off when it happened. It was the main hot at all times lead to the fuse box. No fuses blew, no plugs (except the one this wire passed through) were damaged. The harness I got is the complete underhood harness, and the entire dash harness with the fuse box. The short had to have been between the old harness and the truck, so I am fairly confident it will be OK. And I have fusible links properly installed this time so if there is an issue the harness won't go up in smoke. Turns out some of the stuff needed for the ammeter was removed from my original harness, so maybe that will work now too.

 

[John Smith]

The wire is burned from about 12 inches away from the fuse box all the way to the connection for the harness at the positive terminal on the battery. It's hard to tell but it looks like the wire just grounded out under the dash somewhere. I can't think of any other explanation considering the truck was in the garage with the ignition off when it happened. It was the main hot at all times lead to the fuse box. No fuses blew, no plugs (except the one this wire passed through) were damaged. The harness I got is the complete underhood harness, and the entire dash harness with the fuse box. The short had to have been between the old harness and the truck, so I am fairly confident it will be OK. And I have fusible links properly installed this time so if there is an issue the harness won't go up in smoke. Turns out some of the stuff needed for the ammeter was removed from my original harness, so maybe that will work now too.

If you want to get the ammeter working look for the two fuses in the harness that should be hidden under tape and verify they are actually in their holders and not blown. Just follow the white wire with the blue stripe from the battery into the main harness and you should find the two fuse holders under tape.

 

[subzali]

so how much did the harness cost you?

 

[ken_79-fj40]

The fuse holder for the ammeter had been cut out of my old harness by a P/O. I also only had the main lead and one crimped on connector hooked to the alternator. The new harness that I paid 2 bills for has everything. The ammeter fuse holder is there and I put fresh fuses in it. The alternator wiring is correct with the factory plugs, and I finally have my horn wiring working. Before the horns were working from an unfused lead direct to the battery and a lead spliced into the column that grounded them. Now that's right. I got everything in last night but for some reason I have no brake lights or hazards/turn signals. My diagnostic skills and ability to concentrate on wiring diagrams weren't so good at 11:30 last night after a few beers. I do recall having to jump the brake light wire from one light to the other years ago at the back of the truck so perhaps I will start investigating there. I did verify that the brake light switch seems to be working right. One of the green wires at the harness has power and when you push the pedal the other green wire gets power. But that's as far as I got. The turn signals/hazards must be something simple. I get absolutely nothing. No lights, no indicator on the cluster, no click from the flasher relay.