Screwed up Jump Start.

Since I've jumped started a thousand vehicles by now, there had to come a time when I would screw it up and reverse polarity. It's just a shame that I did it with a recently acquired '94 4-runner of my own. Now, the only electrical circuits that were effected were those that turned on when the doors were opened (courtesy and other interior lights), when the key was put in the ingnition (warning buzzer), and the key moved to the ACC setting (radio, side mirror controls, etc.). What should I do to restore these? Your erudite responses will be greatly appreciated.

Reply to
Windsurfer
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Check both, the fuses and loads (bulbs, relays, ect.) and then for correct voltage on each circuit. You might have to break out a wiring schematic.

Reverse polarity jumps are usually quite damaging and quite expensive to repair. I've seen them mostly when wives have been helping, but it can and does happen to anyone. Check your charging system output as well.

I hope for your sake and wallet that the damage is only on the circuits you mentioned. Good luck.

Reply to
user

The most likely thing to check (that nobody ever thinks to check) is for one or more blown fusible links at the battery post. They look like regular wires on the outside, but it's special wire inside that blows just like a big fuse - and when you reverse polarity there are diodes in the alternator (and elsewhere) that will sink a LOT of current and pop the fusible links.

There's one for the alternator output lead, a few for various power feeds to the fuse and relay centers, etc.

If you popped one (or more) links, get a repair kit and follow the instructions carefully - they have special parallel (not the more common butt) splice crimps where they connect to the vehicle wiring, and if you don't overlap and crimp the wires properly it will heat up and pop at the splice point.

Myself, if I could get current ratings I'd go get the high-amp 12V circuit breakers and change them out - that way you don't get stranded by something silly like that, just reset the breaker.

But don't even THINK of doing that on a car still in warranty, or it soon won't be anymore.

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Reply to
Bruce L. Bergman

Check the big fusible links in the fuse box under the hood.

Reply to
Ray O

Sorry, I didn't mention that I already checked the fusible links, fuses and have started on the bulbs. One bulb is o.k., so I am assuming the others are alright, but I am going to check some of them. The charging output is o.k. from what I can tell, but I am going to check it futher. I assume there is a burned out wire and wonder if I should start with the ignition. Unfortunately, the wiring schematic that is in the Hanes manual which I have doesn't include the complete wiring or that of what has failled me. It's too bad that you haven't added anything that I haven't already thought of. I figure there was a surge that blew through the circuits that are triggered by a door opening, but can't really understand why the Acc circuits would blow.

Reply to
Windsurfer

The fusible links look like jumper wires in the fuse box. How did you check the links? Also check continuity between the battery and fuse box.

Reply to
Ray O

What vehicle are you using as a reference, Ray? I have the manual which identifies the fusible links on mine. They aren't the kind I've seen on GM product which has been my main source of reference. I wonder if anyone read my original post through. I've opened the underdash and am going to examine the wiring coming out of the ignition today. It already looks like something burned through the insulation and splattered it. This has brought back memories from the days that I used hot wire cars.

Reply to
Windsurfer

I am using Toyotas in general as a reference. Are you using a factory manual or a Haynes, Chilton, Motor, etc. manual?

When someone reverses polarity during a jump start, one of the 100 amp fuses or a fusible link generally opens up to protect the rest of the circuits in the car. These are usually in the junction box (fuse box) under the hood. The wire type fusible links look like jumper wires between two terminals and do not always give a visual indication that they have blown so they need to be checked with an ohm meter or continuity tester. The 100 amp main fuse should be checked the same way.

Reply to
Ray O

Thanks for all the answers as they have been worth reading. I checked all the fuses again. Low and behold, I found a 15 AMP (The dome) fuse in the engine compartment that had been blown. I must have missed it the first time I checked which is unusual for me. (Is Old Age setting in?) Whatever this brought everything up except the radio. This may not be working for other reasons, though. The former owners were into stereo electronics and had installed and removed a few units leaving a mass of discarded harnesses stuffed behind the sound unit. I'm not sure they had connected this stock equipment correctly when they took their stuff out and put it back in. Whatever, I feel I got off lightly on this. I quickly removed the jumpers once I saw a large spark knowing that it was wrong.

Reply to
Windsurfer

You're welcome, glad to hear you're back on the road!

Reply to
Ray O

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