In short: I need to completely remove at least one wire from the fuse box to where ever it attaches to because the insulation has completely melted. I don’t know how to do this, and need a DIY guide/instructions on what to do.


The full story:
To start, here are photos:
Fuse box labels of what fuse is what
The mess of wires under the fuse box


Melted wire picture 1
Melted wire picture 2
Melted wire picture 3


I made an earlier post about some problems I was having with my parents' 1989 300E. Since then I’ve fixed the AC, supposedly fixed a short on Fuse 9, and patched up the front passenger door’s courtesy light wiring (Fuse C).

I drove the car around for an afternoon and had no issues with the car. When I went into the trunk the next evening, I noticed the trunk light didn’t come on. I checked the fuse box and found Fuse C had blown. As such, I decided to go with mbdoc’s suggestion of using an in-line fuse holder to isolate where the short is rather than check every single thing on that circuit.

Prior to making the decision, I had looked under the fuse box twice to determine how hard it might be to do that. (This was after I had fixed the above listed problems, but before having driven the car around.) Both of those times, the wires were completely fine. After I made the decision to use in-line fuse holders (fuse C had blow again at this point), I went back under the fuse box to take a picture to ask for instructions on how to install the in-line fuse holders. At this point I discovered a wire’s insulation had melted basically from just before it screws into the fuse box to as deep into mess of wires under the fuse box as I can trace. There are several places the insulation is completely gone, and others where other wires’ insulation has melted together with this problematic wire.

The melted wire screws into fuse B. As far as I know, there hasn’t been a problem with that circuit.

I’ve tried unscrewing wires from the fuse box (being sure to label what went where), cutting the electrical tape that bundles large sections of wire together, and slowly prying up the offending wire. However, I still can’t get any of the wires to lift up much and can’t find where the melting stops.

Would someone please provide instructions on how to trace the wire to where it goes, and how to get into the underside of the fuse box with enough room and play in the wires so I can replace said wire and do necessary taping on nearly wires?


Is there any possible way to figure out what caused the problem? I’m afraid if I fix the wires without fixing the problem, wires could just melt again and/or I’ll have an electrical fire on my hands.


-Hope