Fire Damage Wiring Repair

And the Nightmare Continues...

Now the instrument cluster and radio lights come on when the ignition sw. is on; headlights will not come on at all.

Missing a ground or a blown fuse link wire or both maybe?

The fuse links are at the end of the battery cable where it hooks to the power distribution box. They are fat soft wires with large rubber tube crimps where they join the wiring harness.

My money is on a missing ground for the dash....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

Mike:

Do you mean where the positive battery wire attaches to the junction box? I have been wanting to find these fusible links as the next step in my diagnostic process, so any information will be very helpful. My manuals are no help on this.

Randall

You have a Wagoneer right? The big one I am now thinking?

Anyhow, follow the positive wire and at the first bolt connector you come to there should be some loop connectors for other wiring connected to this same bolt. It could be on the solenoid if you have one or a junction box or relay.

These loop connectors have soft rubber coated wires about 8" long on them and then a large rubber tube type crimp connector where they connect to the wiring harness component's larger plastic coated wire.

You also can follow the red wire off the alternator and find them where it's fuse link joins the battery cable. They all join at the same place I believe.

Most of them are 14 ga. protecting 10 ga. circuits. You can buy bulk wire and they need to be crimp connected only. Solder will damage them.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Mike:

Yes, Grand Wagoneer.

I will start in first thing in the morning to locate these "fusible links" as the manual calls them. I suspect a fault in one, which causes the instrument lights to illuminate any time the ignition switch is "on". I am also blowing a fuse every time the dimmer switch is activated or the lights are on "Low" Beam.

Randall Brink

Are you 100% sure that the fuse being blown is the right rating?

Does turning the light switch handle make the instrument panel go bright and dim? It should.

If you have power, then it is unlikely that there is a problem in the fusible link or links. It certainly wouldn't hurt to locate them, perform a visual inspection and verify continuity.

When you get done with this job, you will have accumulated enough expertise to hang up a shingle and go into business. :^)

Earle

They won't be the location of the short. When these fuse links mess up, they just blow.

You really sound like you have a short inside the wiring harness. That big headlight wire that melted down the light switch has very likely melted into something else.

Well, not 'likely' pretty much for sure by the sound of your symptoms.

Just so you know, the wiring harness comes apart into modules that all meet at the fuse panel. If you go on the engine side of the fuse panel, you will find one bolt in the center of it. This bolt will force the panel to come apart into it's components so you can maybe get a better bead on it.

I foresee a lot of cutting of harness covering. You can get the split corrugated tube loom to put the wires back into once you have opened up the harness. You can even tuck it into the loom as you cut it open and inspect it so you don't have a total rats nest.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Before digging into the wiring harness, I suggest double-checking to make sure that all the wires on the switch are hooked up right. I am thinking that two wires interchanged by accident could produce similar symptoms.

This job has to be a nightmare. Not too many amateur mechanics would have gotten this far.

Earle

Oh, what fuse are you blowing?

The headlights are not fused...

Mike

" snipped-for-privacy@adelphia.net" wrote:

Earle:

I am fairly certain about the fuse--it is a 20 amp, as are most of the fuses in that panel, and I believe it is marked "20".

I do not believe that the dash lights dim properly, I think they remain on one constant brightness level. I will check this when I get the Jeep into the shop this afternoon. This dash light thing is very weird to me, and I am having trouble figuring that out.

I have a growing suspicion that you're right about the short, except that the high beam headlights are the only accessory that blows the fuse and the rest of the many components on that switch all work.

Also, and this may or may not be relevant, but it was the rear part of the switch that fried, where the park, dash and dome light wires come into the switch block.

If in light of this, you still believe that there is a short in the main (12 ga.) power supply wire, then I will start investigating the wire loom--a major undertaking, indeed!

Thanks again!

Randall Brink

Well, I am firmly in the column of "amateur" but as you pointed out, I am gaining valuable experience through all of this, and the consolation is, I am much less intmidated by any mechanical task on the Jeep now. I believe that if you are going to own these wonderful old machines, you've got to be willing to get right into whatever mechanical problem presents itself.

Regarding the prospect of the switched wires, I am still willling to believe in that possibility, despite having meticulously tagged, taped off and marked, all wires prior to splicing the switch connector wires.

Bearing in mind that I did not remove the dash, and merely worked through the instrument panel opening, and had to splice and solder in that space, anything is possible.

Mentally, though, I'm having a hard time getting around the idea that the only wires that could have been switched, i.e., the "dual wire" connectors, are for the park lights and the headlighrs, which all work, and the only single wire, other than the dome light wire, which is black, is the single dash light wire, a stripped red wire. If that striped red wire were swapped with the striped red wire in the headlight connector, I would surmise that neither the headlights nor the dash lights would work at all. Of course, I could be wrong.

Randall

I am getting really mixed up here....

I thought it was the low beams that blew the fuse?

What fuse is blowing?

Headlights are 'not' fused.

Ok, just for the heck of it I would have a look at the dimmer switch too. I recently burned out my CJ7's headlight switch, the same red wire melted the big plug all to shit and it also melted my dimmer switch.

I left the damn thing alone because it was only 5 years old and wired a rocker switch for my headlights. I now have super white headlights but my interior lights don't work anymore....

My CJ7 has the same GM light wiring as your FSJ.

Mike

" snipped-for-privacy@adelphia.net" wrote:

Woah now.

The only black wires om my headlight switch are from the front corner of the plug and are the switch 'grounds'. They are not power lines.

The red wire with the white stripe on my switch is for the headlights. It goes to the dimmer switch.

Mike

is the single dash light wire, a stripped red wire. If that

I'm getting lost in your symptoms here.

You had an electrical fire of unknown cause at your GM-style light switch and replaced the switch and pigtailed harness. You are certain that you wired the switch the same way that it was.

Now your highbeams or low beams blows a fuse. Which fuse? What legend appears next to it at the fuseblock? What (else) goes out when that fuse pops? (Fuses pop for one of three reasons: Accessory overload, short to ground before the load or local overheating.)

Your dash lights come on with the keyswitch in the ON position with the light switch OFF? This would be general instrument illumination lights? The ones that can be dimmed down with the reostat? Can they be dimmed at all? Do they work with the key off?

The reostat on the light switch now becomes smoking hot. In all positions or only with the dome light is switched on? Does it matter if the door is open?

A left-field question: Has the radio recently been replaced? Lighting and keyswitch-controlled accessories are generally well seperated electrically, but the radio is often one place with both feeds plus a B+ feed.

snipped-for-privacy@adelphia.net wrote:

Mike:

Yes, it is the high beams that blows the fuse. I am going to replace the dimmer switch today and see if that cures that problem.

Please tell us 'what' fuse blows. Even it's location in the panel, then I can look in my book and maybe see what circuit is bad.

The headlights are 'not' fused so something else is shorted with the highbeam wiring.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

That's not going to help your problem with the panel lights. Apart from enjoying a common power feed at the light switch they're completely separate.

In previous posts I took you use of "dimmer" to mean the rheostat on the back of the light switch. Was I mistaken?

Which fuse are you blowing?

snipped-for-privacy@adelphia.net wrote:

Believe it or not, this time NO FUSE blew, and the headlights still do not work. Barring an unlikely dual-headlight simultaneous burn-out, I am again at a loss...