Electrical Issues

[CharlieG]

The quick issue: I have a '93 ls400. I reversed the polarity when trying to jump my car and then nothing would work. I checked and replaced the blown out fuses that I could easily take out and the 120 amp fuses that are sort of isolated. The car runs now and headlights and break lights come on and work properly. The problem is that my radio, inner lights, alarm, all door lock/unlock, trunk switch, adjustable steering column, adjustable mirrors, and back-light on the rear-view mirror do not work. Also, when i turn the car off and back on, my heat settings reset to the coldest temperature and floor only. I am hoping that I just missed a major fuse or something. Help?

The long, descriptive issue: I have a '93 ls400. So I am an idiot and reversed my polarity when jumping my car assuming I knew exactly which was + and - in the dark. It was only on for like 2 seconds and then I realized it. Of coarse I blew some major fuses and nothing would turn on and the car would only start when attached to another battery. It would turn off in like 2 seconds when disconnected. So I checked and replaced the fuses that I knew how to (or looked up how to). Pretty much they were the 120 amp fuses that are isolated under the hood and all of the 15 amp and below fuses under the hood and the "kick panel" ones. So I got the car to start and maintain a charge, the headlights and brake-lights to turn on and work properly, and the power windows to work. The major problem is that nothing else works (radio, inner lights, alarm, all door lock/unlock, trunk switch, adjustable steering column, adjustable mirrors, and back-light on the rear-view mirror). I could not figure out how to check and replace the 30 amp fuses or any other one that does not simply come out besides the 120 amps fuses. I'm sure they are bolted down like the other ones and will be working on getting them out. Any help will be greatly appreciated.

[landar]

I guess you have learned a valuable lesson not to do THAT again (reverse polarity). So chalk it up to experience. From the sounds of it, you just missed replacing a fuse and will need to methodically track them all down and test.

I just hope you did not whack a control computer somewhere. The radio not working should make it relatively easy to check the radio fuse. And make sure to use a continuity tester to check the fuses, like an ohmmeter or test light. Sometimes a visual check looks ok but is not. Do the cigarette lighters work?

[billydpowell]

I have never been where you are at, but feeling that the electrical items are fused, in my mind, I would go to a salvage yard and buy the unit under the hood, and wire it in and see where you are at that point. and go from there.

or even use the relays & fuses to put in yours.... but when you remove one of yours check the terminals to see if they are burned...

[dulobast25]

find out which fuse feeds all of the items u mentioned. Settings lost indicates a loss of unswitced dec 12+ and not ignition I would be a fusible link as well.

[steve2006]

Recheck all fuses particularly 4 Radio fuse 7.5A, 9 ECU-IG fuse 15A, 18 Radio no.1 20A the one fuse common to all the faulty items is Fuse 20 DOME 10A.

Also check the 3 circuit breakers in the internal fuse panel there is a little hole in the top of the casing where you can insert a probe and push in to reset them.

I would recheck fuse 20 first before continuing.

All the fuse positions should be marked on the fuse panel cover.

[dulobast25]

exactly, if the problem were at the battery and main battm post, you would have mor eproblems that that. The fact that you have the problem amonst mor ethan one item woudl indicata a problem at the source of jus those items or the gnd at just thoe items. Problems with the 12+ side is mor elikely based upon the events that led up to your symptoms. One approach would be to provide a 10 a fused source of power at the 12v side of any othe items that have failed. if you have s hort, the 10a fuse would burn out. If you have an open, then all of the items not working would energized, indication the the 12v cirucit feeding all of them has a bad fuse or has burned open.

Let me know if you follow my explanation.