help me, I have a battery problem !
 

Hi I drive an 85 300zx GL . About 2 years ago I put a new alternator in it. Just yestaerday I was driving home from a short drive. The headlights, all of the instruments dimmed, the vlot meter started sinking down to 8 volts. I Made it home, took the battery to autozone. They replaced it with a new one. I have the same problem with the new battery. is there a solution to this ?

Yes. The solution could be as simple as an alternator belt, or, as complex as a complete alternator. Either way, you're not producing electricity.

Take the entire car to AutoZone. They will test the charging system for you, advise you of what part(s) you need, and sell them to you, right there, on the spot. Take your own wrenches though, they'll only do battery installations. :cool:

voltage regulator
 

Thanks for the tip, could it also be the voltage regulator ? When I turn on the stereo, and turn up the volume, it shuts off. Headlamps on dim, ac slows down. could it be that as well ?

it could be the voltage regulator, but on the newer Z cars (280zx and up) I believe they came with an internal voltage regulator built into the alternator.

bad relay
 

can it be a bad relay, and which relay would it be, if the alternator was shot, wouldn't the guage light illuminate ?

make sure all of your connections going to your alternator are hooked up and tight. If they aren't, you can easily fry an alternator. I'd take the alternator out of the car, take it to autozone/kragen/napa, and have them check it on their machine.

I doubt that it's a voltage regulator... check your fusible links, you've got a short in the main Battery link... alot of Z31's have this problem, I've worked on 4 other Z's than my own...and every last one of them has had this problem, if your vehicle is pre-owned, in most cases...the majority of Z31's are... check the fusible link box, located infront of your batter, on the passenger side fenderwall... it will be the first connection on the right, if you're standing infront of your of your front passenger wheel. Often, people will twist these links together once they've blown, because they just don't know how to fix it, or didn't think to replace it with a new one. If this is your problem, which I suspect it is... it was my problem. I would go to your nearest Nissan dealership, and buy a replacement, if the replacement blows...then you've got an electricl short between the link and the battery connection. Good luck

JD