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Headlights and Brakelights cause car to quit


Guest Boyd

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OK guys, I need some quick suggestions on an electrical problem.

 

Here's what happens:

 

With the engine running or not, I can have the key swith on and press the brakes, which then causes the ammeter(SP?) to peg out negative. If the engine is running when I do this, it will kill the engine. I occasionally hear the belt squeel. Similar thing happens when I turn on the headlights, which lead my friend to believe there is a problem in the taillights somewhere.

 

Overall, the wiring in the car hasn't been modified that much, so it leads me to think wire shielding has been rubbed away and it grounding out to the chassis, but there are so many wires I don't where to start!

 

Anybody seen this before or have some quick suggestions?

 

Reynolds

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Guest dpiatkin

sounds more like you have a bad alternator and the car is running off of battery only...... start the car and pull the + cable while its running, if it dies you have a bad alternator..... if not check elsewhere.

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I pulled the battery lead and the car still runs, but I still wonder if the load could be causing the alternator regulator to wig out?

 

I could pull the alternator in about 15 minutes and go have it checked.

 

Thanks for the reply!

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If the Amp meter is pegging, I'd suspect a short. Have someone hit the brakes and see if the taillights look different, this might point you in the directiion of the short. If you were working someplace between the firewall and the taillights just before this problem started, start checking in that area. Look for a cooked wire, if it's pulling that much power something should have fried. Get a VOM meter and study the wire diagram. Good luck, finding a short can be a real PIA. Try starting at the taillights and see if you can find ground at the +12 terminals, that would isolate a circuit for you.

 

- Joe

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  • 4 weeks later...

Ok guys, I have looked at this problem some more. Here is what I have found.

 

With key off, ammeter registers normally. If I turn the key on, it pegs out to the left or negative. If I turn key to START position, all reads fine and I then hear the fuel pump start.

 

Also, with key off, I can turn on the headlights or press the brakes and the ammeter with go from registering normally to pegged out negative.

 

I am not very good with automotive wiring, but I am getting closer to wanting to rewire the entire car.

 

Does anyone have any thoughts before I consider this? :?:

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I just went back out after letting the battery charger run awhile. I turned the key on and everything worked fine, but as soon as I touched the brake pedal, the ammeter pegged out and stayed there. I turned key off and on several times and it finally went back to working. :!:

 

I wonder if the battery itself could be blamed? Somehow reversing polarity. I have never heard of it, but the battery is old.

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How about trying what the people above suggested? :?

 

Sorry, didn't post results, just kept on going!

 

I have tried the things listed above, except for unplugging the brakelight switch, will do that test next.

 

There just doesn't seem to be much rhyme or reason to this problem. Really bizarre. Gonna have to spend some serious time on it.

 

I'll take some good notes and post them up, maybe someone will have seen this before or can pinpoint the problem.

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sounds more like you have a bad alternator and the car is running off of battery only...... start the car and pull the + cable while its running, if it dies you have a bad alternator..... if not check elsewhere.

 

I pulled the battery cable while the engine was running without it killing the engine, so alternator seems fine.

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If the Amp meter is pegging' date=' I'd suspect a short. Have someone hit the brakes and see if the taillights look different, this might point you in the directiion of the short. If you were working someplace between the firewall and the taillights just before this problem started, start checking in that area. Look for a cooked wire, if it's pulling that much power something should have fried. Get a VOM meter and study the wire diagram. Good luck, finding a short can be a real PIA. Try starting at the taillights and see if you can find ground at the +12 terminals, that would isolate a circuit for you.

 

- Joe[/quote']

 

I had my wife press the break pedal with I looked at the brake lights. They did not come on. I have been looking for a cooked wire, but so far haven't found anything but a corroded plug that goes to the headlamps. I disconnected it and still have the same problems. I also found ground connections on the tail lights where there shouldn't be. I am waiting for the weather to clear up so I can crawl under the car and inspect the wiring a bit closer.

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Can you still buy fusible link wires at dealerships? I am going to call the local dealership today and see if they have them.

 

I am in Alabama and it is still cold and wet here, not favorable weather to be working on a car out in a rocky driveway. :cry:

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did you ever try unplugging the brake switch?

 

I just tried unplugging the brake switch and it didn't make any difference. I have unplugged the headlamps too, just before the radiator support.

 

I have also noticed that if I move the key from the ON to the START position that my fuel pump finally comes on.

 

I checked for resistance on the fusible links against GROUND and found that one of the connectors is getting solid ground, but haven't been able to trace it back looking at the manual. It's the front fusible link box, the connector closest to the fender and to the rear.

 

Sun just came out! Whoohooo!!! Maybe I can work on the car a bit today!

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I think I may have narrowed it down to the ignition relay, when looks to control more than the ignition.

 

On a side note, think I may have a couple bad injectors. The engine got flooded with gas twice, the second time the injector clips weren't even connected. :?

 

Guess I'll step up from the 295cc and go for some 370's or 440's.

 

This car is kicking me in the ass too much, and not the type kick in the ass I have been looking for.

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Well, the Z is on the trailer, ready to move. I have given up on it until we get moved into our new place and have a decent place to work. I will also be in a large enough town to get some decent performance parts and services.

 

Ever winched a 280Z onto a trailer with just a come-a-long? Light car, but it is still back breaking!

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