completely rewire fuse box or delete it?

My 89 has had far to many electrical gremlins originating from the fuse box.
Ive dropped it twice since ive owned it to find corrosion crawling up wires under the insulation 2-3 inches.

My current problem is the park, tail, instrument light circuit.
the fuse is getting so hot the plastic is bubling up and melting...dash lights go out with an audible click from the headlight switch and tail and park lights go out at the same time so I assume they are on the same circuit but I see a separate fuse for dash lights?

I faced this before on another circuit and it ended up being high resitance due to corrosion in the wires at the fuse box (yes this is a 5 speed and yes it had clutch fluid dripping onto the fuse box when I bought it)
Im tired of fighting this battle so I was thinking about running inline fueses rewired to existing good wire that isnt corroded....
Thoughts?
does the headlightswitch have some kind of thermal cutoff built into it? Icant figure out why the instrument lights go out but the fuse isnt blowing....

Ok when I pull the instrument illumination fuse the park and tail circuit stays on but when I plug the instrument fuse in the park/tail/ lights go out after I see smoke from the fuse box.......can this be headlight switch related or do I have to seperate circuits back feeding together?

the park/tail 10 amp fuse
and the instrument light 5amp fuse
are separate circuits right?

when I pull the 10 amp fuse instrument lights go out.....seems like instrument lights and park/tail are feeding on the same circuit?

How is it that you get clutch fluid dripping into fuse box? Please explain. Thanks.

The park/taillight fuse supplies power to the dimmer in the headlight switch, power out of the dimmer to the Instru Light fuse then back up to the instrument lights, clock, ashtray etc.


gratis bilder hochladen

A lot can go wrong in this circuit. Most times it is a shorted dimmer (coil resistor) in the headlight switch. This can cascade and partially melt the headlight connector and even some wiring. That dimmer coil can get really hot, one way to tell is to touch the rod for your headlight switch with the knob pulled out. Be careful not to blister the end of your finger.

If you've had a wire meltdown no telling where the problem is, it may be in the harness from the fuse box going up.

Even the clock can cause a short in this circuit, it has happened at least once that I know of.

I bypassed the dimmer on mine at the fuse block and ran a new wire up to the splice near the instrument cluster connector. I had a partial meltdown inside the harness and a partial meltdown at the headlight switch connector. I believe the major malfunction was a dimmer coil short and the heat did the rest of the damage. I replaced two headlight switches in a two year period because of that dimmer resistor coil. Now I only have full bright, but this switch has lasted for the last 6-7 years since I bypassed the dimmer.

The headlight switch has a built in circuit breaker.

Alaskan89XJ said:

How is it that you get clutch fluid dripping into fuse box? Please explain. Thanks.

Click to expand...

My YJ did that, the clutch is hydraulic, with a master and slave cylinder. If the master leaks the DOT 3 fluid often runs down the inside of the firewall.

So its feasible that a bad headlight switch can be causing this?
after all it does control all these functions
you said th3 headlight switch has a built in circuit breaker? That confirms my suspicions

outlander said:

So its feasible that a bad headlight switch can be causing this?
after all it does control all these functions
you said th3 headlight switch has a built in circuit breaker? That confirms my suspicions

Click to expand...

There was an argument about the headlight dimmer blowing the park taillight fuse awhile back, I said yes, somebody else says no. It is likely to be the headlight switch. But it may be a short someplace else. That dimmer resistor coil in the headlight switch, when it shorts out, gets hot enough to turn the wires blue and melt connectors. A short in the dash lighting circuit is more likely to blow the instru fuse and not the park/taillight fuse, but it is possible for a shorted/melted wire in the harness to blow both.