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Trying to replace a corroded wire in a 97 Subaru Legacy - STUCK!

Hello all,

I’ll try to be brief. 97 subaru Legacy GT 2.5. At one point, in heavy Chicago traffic moving at a pretty good clip, a semi-truck tire exploded a few cars a head of us, I basically had to run part of the tire over in order to not get in an accident. This ripped off the driver’s side fender liner.

Flash forward a year or so. Major electrical problems. Not starting. Or starting then behaving erratically. Things shutting on or off. Then nothing. It ended up being a corroded wire that comes out of the bottom of the fuse box in the engine bay and heads out the driver’s side fender and then one part of this harness goes up along the inner/upper fender towards the front (lights I’m assuming), and then the other heads up/inside the fender toward the firewall. I’m assuming that this is where the bad wire goes.

It’s actually TWO wires that clip into a plastic housing, which then clips into the bottom of the engine bay fuse box. The fuses directly above where they plug in say “SMB” according to the diagram on the cover (i think that’s what they are labeled as) and there are 3 of them in a row.

When this happened the first time, I used butt-splices and some new 10-12ga wire to patch it. Worked fine. Now, that’s been corroded again (yes, i should have replaced the fender liner, but I let it slip, and so here we are again) and i’ve tried repairing it and i’m getting nothing.

Here’s the thing though: These two cables actually were joined at one point from the factory. By that I mean that, coming from the box down, they are two cables. Then, a few inches along, they are joined together, wrapped in a rubber jacket about an inch to an inch and a half long. Then they come out two separate cables again. This is all been corroded and had to be cut away. I have tried recreating that joint but to no avail. When the repair-attempt-cabling is not plugged to the fuse box, and the key is ON but not at Ignition, the car dings normally. Once I plug it in, it gets weak and feeble. a few dash lights dimly flicker and there is nothing I try to start it.

I’ve tried butt-joints and several soldering jobs. Though I’m clearly no wiring expert and my soldering leaves a lot to be desired so I have little confidence in the job I’m doing in that department.

One other thing to this saga is that, when this happened most recently, it was in a parking ramp and my first few attempts to fix it, seemed like it would work, all the electronics seemed happy as you turned the key on. Then as it would go to start, it would do a big click as if it was going to start, then absolutely nothing. This happend for a few soldering attempts, then it started doing the “weak” dinging/dash lights thing mentioned above. Now it’s been towed home.

I’m really stuck. All the parts stores don’t sell specific cables and say you “just make your own” and are baffled when I tell them of the “Joint” nature of this cable. the dealer wants $650 for a new harness. The stupid savlage yard I usually go to screwed up on the special pull they were supposed to do and cut/threw away the fuse box and wiring I wanted (i did get a liner though, classic too little too late).

Anything anyone can think of? What is that cable? Why is it joined? How can I re-create? Correct soldering/splicing procedure?

Attached is a pic. THANKS FOR YOUR TIME!

How exactly did you handle recreating the “joint?” Are the wires individually wrapped inside their cocoon? Did you use the same gauge wire as the factory used? Have you checked all your solder joins and splices with a multimeter to be sure they’re correct?

They are not wrapped individually, they are making contact.

I stripped ~3/4" or so off of each end of the wire (appears to be same gauge as factory), two wires on this end, two wires on that end, both ends twisted together, then did my best to twist the pairs together, then soldered that joint (heating the wire, not the solder). I suppose now that I’m writing that out here, i should try using a razor to strip a section of the wires uncut, then solder the bare sections together…thoughts?

I haven’t checked anything with a multimeter. I do have one, but I’m not sure what I’m checking. Should I be seeing the battery’s ~12volts with the key ON? Thanks.

You might also try posting to the Subaru forums - someone there may have specific information if we can’t help you. (I know I can’t, but there are some really great people here. )

You stated that when you connect those wires to the fuse panel it causes things to act strangely. This is because the wire is adding more load to the fuse panel and you appear to have a bad connection to the main battery supply. The bad connection causes resistance in the line and when you add more load to it then more voltage gets dropped across the bad connection.

It would help to have a voltmeter in order to check things and there are many available at prices starting around 20 dollars. Check the small wire that connects to the positive battery post and follow it to the fuse panel under the hood. Look for a bad connection. Also clean the battery to chassis ground connection.