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Unread 06-19-2017, 06:55 AM   #1
Join Date: Jun 2017
Posts: 1
Unhappy Short inside engine fuse box, repair?

I seem to have a very bad problem, which I desperately need help with. I have 1999 4Runner in outstanding condition, no rust, kept up, everything works perfectly, etc., and in a rare configuration (5-speed and 4WD) except for one thing... it seems to have developed a short inside the engine fuse box. Now it does not seem that this box can be opened, to be repaired. It seems that it is integral with the rest of the wiring harness, and it does not seem that there are any available from Toyota. My mechanics have it all apart, and say they can't find the part.

What can I do? Am I supposed to trash an otherwise perfectly good 4Runner, worth on the order of $10-$12K, because of a short?


As background, let me explain a few things. First of all, it has always had a few electrical gremlins. It would put the rear window down, at random, on occasion, without input from me (without the ignition turned on). It would also lock itself on a regular basis. Then, a few days before the next stage (to be described), the guages in the instrument cluster, plus cruise control, AC and backup lights failed. The "guage" fuse was burned out, inside the car, but when I replaced it, it lasted only a second before blowing the new fuse.

This crisis began when one day (a week or so after the guage fuse burned out) it failed to start. I just happened to be outside an auto repair shop (Midas, where I had taken my wife's car). It was determined by those mechanics that the alternator had failed, and so they replaced that and the battery. It seemed fine for a day, then I drove it 50 miles, in the day, including stops, and then, when I drove it another 25 miles, the last half at night, with lights, the battery ran down, the lights dimmed and the car died.

So I had it towed back to the shop that replaced the alternator (Midas), and they tested everything, and discovered that it had a huge current drain which originated in the engine fuse box. Now it is completely apart, and they say they can't get the part.

What can I do? Do I need to use a second-hand part, which the shop cannot guarantee? Just getting one out of the donor is quite a bit of work... This all costs quite a bit...

Last edited by yankee2; 06-19-2017 at 07:04 AM. Reason: To improve my explanation
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Unread 06-19-2017, 07:50 AM   #2
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Join Date: May 2005
Location: Walnut Creek, CA
Posts: 12,314

This sounds like a very tough problem. However I am a bit skeptical about a short in the fuse box itself. It may take a while to troubleshoot, but perhaps pull all the fuses and relays (clearly marking them off course). Then see if you still have the current drain from the battery.

Check you major circuits, like the ones going to alternator and starter. Also check all your ground connections and wires. See if you can isolate where this drain/short is located. Also check the fuse box and wiring harness for signs of melting plastic.

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electrical, fuse, fuse box fault, harness

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