Thread: Big Electrical Problem

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So I have a 1997 Nissan Pickup and the other day i decided to wire up some new things. I did the Big 3 upgrade and installed a capacitor for my sound system. The system now has two amps(one for a sub and one for my four speakers), a sub, a Kenwood head unit, Kenwood speakers, and now a capacitor. As I was wiring up the Big 3 upgrade I had neglected to unhook the battery and when I was lossening the positive connection on the alternator I swung the wrench too far back and it got wedged between the alt. and a mounting bracket. Some little sprks were going and after about 5 seconds I heard a little bit of a pop. I knew right then that things weren't going to be good. I finished up what I was doing and tunred the pickup on. It starts, runs, and my headlights work(brights and all), but my radio, horn, interrior lights, guage lights, blower motor, ect... do not. The only light in the dash that comes on is the battery emblem when it's running and the bright emlblem when I turn on the high beams. None of my fuses are blown and I have 13.4 volts at the battery. (the capacitor and amp also light up so i have power there) If anyone can help it would be much appreciated, and a Merry Christmas to all.

Is there a fuse-able link somewhere? I lost dash lights & starter on my Chevy P.U. last summer. Turned out to be a fuse-able link on the firewall that fried. It fried because the ignition wire to the starter solenoid was worn bare and touching the frame. Took a couple fuse-able link replacements before I tracked down the source since it was one of those intermittent deals. I'd go for weeks before it would happen again. I've been good to go since I fixed the bare wire.
Could be the pop you heard was the link blowing?

ProZ and I were typing at the same time.... Hard to tell without a schematic, but my first thought is you blew a fusible link by shorting the alternator to ground, or perhaps the internal regulator on the alternator. The alternator obviously works as you're seeing 13.4 volts at the battery. I would probably take the alternator to a good parts store and have it checked if it were mine, then start looking for a wiring diagram to see what components you're dealing with...

There may be a wiring dia. in the back of your owners manual or a ref. in the table of contents.

Thanks for the help everyone. I read somewhere that unhooking the ground of the battery while the vehicle is runnning can test the alternator so i think i'll try that and then look for any blown fuses.

Also check for a tripped circuit breaker somewhere in the engine compartment; since you heard a pop, if it was a breaker, it would be fairly close to where you were working.

Originally Posted by Z28Dylan

Thanks for the help everyone. I read somewhere that unhooking the ground of the battery while the vehicle is runnning can test the alternator so i think i'll try that and then look for any blown fuses.

I WOULD NOT try that! Opening the circuit will surge the electrical systems and you run the risk of losing every computer in the vehicle! That was a test "Back in the Day".... My .02 cents.

Nissan has some pretty crafty ways of laying out the circuitry in their vehicles,they are very sensitive to grounding issues and some of the grounds control multiple modules inside the car, it is very easy to overlook this when grounding multiple items into an existing ground location and it can result in some serious ECU ECM issues although the vehicle may still run and drive fine. To be safe I would undo everything you have done and see if that corrects the issue,if so consider taking your equipment to a shop that does the installs every day (you may already know what your doing Im not trying to be mean or anything) that way if something goes wrong you have someone to be held accountable, those Nisssan computer modules are extremely expensive. Good Luck.