1995 Subaru SVX Fuse-Blowing Mystery

My question to the brain-trust is if it is feasible to connect a continuity meter between the line load side of the fuse socket and the chassis, then look for resistance changes as I wiggle, move the bundles of wires.

Might work, but most of the wires are going to be bundled together pretty tight in the harness. You might have to do a lot of unwrapping and then re-wrapping.

You might try checking for a short on the key switch first before that pain.

Edit: Check for burn marks where the bundle(s) go through the firewall. The grommets get dried out, crack, and then normal vibration chews through the insulation.

https://www.youtube.com/watch?v=ufVuWznmJLA

Does she recall passing a Chevy Cavalier?

*Any* Chevy Cavalier?

you mean: did she hit one?

I would bypass the fuse and hold the wire completing the circuit by hand, in the daylight wait for smoke, at night look for spark....feel for heat with hand if nothing sighted....make sure you have isolated everything you can first though...I would put an amp probe on there first, for a visual on the short...or as someone suggested, a light...You're going to have to make a repair anyway, why waste all day looking for it....Don't leave it shorted too long or you could damage the battery....just a few seconds at a time...

Like it, my thoughts too......

Connect a twelve-volt buzzer or Sonalert® by wiring/soldering its terminals to a "blown" fuse with short lengths of wire. Plug the "adapter" fuse into the fuse block, and, if a short is occurring in that circuit, the noisemaker will, uh, make noise as soon as power is supplied. Disconnect and wiggle things until the noise either stutters or stops, and you will have found the short.

Please, note that this won't work if the circuit requires more than just a bit of power; the circuit impedance/resistance, even if operating correctly, will be low enough that the buzzer will sound. In that case, the devices supplied by that circuit must be disconnected before fiddling with the wiring.

Alarm bell went on when you said : "Daughter".

I would quizz her if she hit something (like a Chavalier haha) or anything.

A cable sqeezed under plastic will not be noted unless you know where it was hit.

Other than that what does the code reader come up with? I know you have it in the shop, but what are they saying?

I had this on a Mazda about 40 years ago. I could not get at the wire without taking the engine and gearbox out. The wire ran from the ignition switch, thru the firewall to the engine....the short to frame was between firewall and engine.

Got the car schematic, cut the wire at fault at both ends and ran a new one, problem solved.

Took a whole weekend of work!!!

THANKS to all who offered good suggestions! I have the schematics that allowed me to isolate vulnerable downstream components. It's been sitting in my workshop waiting for weather to break. I didn't ask her if she was within a half-mile of a Cavalier at any point, and I'll look into that too!

Yes, use a continuity tester. See below. They will come with instructions on how to use. The needle point allows you to pierce wires without ruining them and to get into tight spaces.

Here's a circuit to build one for an audible tester

I've had good luck with one of these. Based on the readout you get an idea if it's a dead short, intermittent, through a coil, light bulb, etc.