Supra Wiring/Fuse Problems Need Help!!!
 

I have been having some problems with my 86 Supra. The windows, reverse lights, and the heater/rear defogger are failing. Everytime I put in a new fuse it pops! Heard some rumbling in the dash just before the fuse had popped the first time. Can any one give me some info before i take my dash apart? Please help me!

Thanks,
Krista

rumbling...? never heard that before, u might have a short somewhere coming from teh fuse box....thats my diagnostic...check connections...

yes you have a short circuit (to ground). either a wire or a connector cut or something to make contact with ground (chassis or negative) or a motor (the load for the circuit) doesn't have enough resistance. Either way theres not enough resistance in the circuit to keep the current below what its fused for. Whatever you do dont just put a bigger fuse in. The factory already has a 30% lee-way just incase of spikes. Basically your going to need a voltmeter at the least to tackle this one, the only problem is that you need to know how to use it. Im going to take a wild guess and say its probabably window switch related. but thats just because i know window switches fail quite often on other vehicles.

Sorry for the essay. If you can get a wiring diagram or manual i can probably help you further.

Thanks for your suggestion. I do have an ohm/voltmeter and the diagram is somewhere in the basement, just need to look for it. ghettie had the same problem and I was hoping he finally figured it out and posted something to the web. I am not looking forward to isolating all the circuits to locate the problem, but I will start with the windows. I am bought the car over two years ago and i am hoping that the previous owner didn't change any of the wiring, so the schematics will be exact. I appreciate your help.

If anyone else has any ideas, I appreciate all of your input.

Can anyone tell me what is fed by the yellow Gauge(15) fuse wire in the connector? I traced the short to that wire and removed it from the connector, but the diagrams I have don't tell me where it feeds to. I now have windows and the fan blower works, but no back up lights, rear defogger, gauges or heat.

pull the fuse block out, supras had a problem of leaking at the bottom of the windshield and the water would corrode the back of the fuse block. I replaced quite a number of fuse blocks while working at the toyota dealership because of this problem. it really wreaks havoc on the electrical system, very hard to diagnose if you don't know about the leaking problem.

I have a similar problem...my interior lightsa dont work (by the rearview), the ones in the visors work fine thou. and my factory clock comes on and off. and i was trying to install the stereo and i tested every wire in there and none were powered. the previous owner installed/removed an aftermarket stereo before i got the car. But...i was guessing it was a fuse. but i am missing the cover with the diagram on it. so could anyone help me with this, or tell me whee to find it?

some had a radio fuse in the kickpanel
others had the fuse in the block in the engine bay... try the kickpanel first for power for the stereo
as for int lights... replace teh fuse and see if it goes poof again ;)

The problem is i dont have the fuse panel cover so i dont know which fuse to look at. there was like 30 under there and im not taking all of them out. Unless i cant find the fuse block diagram somewhere