300zx BATTERY LIGHT STAYS ON

[rewjr69]

90 300ZX NA

My battery light is on constantly. When I depress the brake pedal, the light becomes very bright. All lights and the stereo work perfectly...Although sometimes the battery light blinks in sync with the music.

My battery has is new from Sears. I've cleaned the terminals and sprayed anti-corrosive spray onto the terminals.
I've also checked the ground....any advice???

[88Z+2010Rogue]

Your alternator is on its way out.

[rewjr69]

Your alternator is on its way out.

EVEN IF THE LIGHT IS REALLY DIM MOST OF THE TIME??

[88Z+2010Rogue]

If battery is new then it's definitely the alternator.
How long has the light been on?

[rewjr69]

If battery is new then it's definitely the alternator.
How long has the light been on?

Maybe the last 3 months or so. Sometimes my amplifier cuts off when I rev

[88Z+2010Rogue]

I'd go to pep boys and have them test the alternator. They do it for free.

[NORCAL300ZX916]

if u have a volt meter your cars voltage when running should be between 13.8 and 14.4v. then put the a/c on high and the high beams on, the voltage will drop but should promptly return to the 13.8-14.4v range. if not your voltage regulator(inside the alternator) or your alternator is bad, either way your in need of a new alternator.

[NORCAL300ZX916]

another(less sophisticated) way to test the alternator is to remove one battery terminal when the car is running. it should run no problem if it dies or acts like its going to your alternator... blows. you should be able to run a/c on high and high beams with one battery terminal off.

[rewjr69]

it was the alternator. problem solved. thanks!!!!!!!!!

[TVdude]

My battery and brake light came on today. It went away for a few minutes but it came back on, I'm gonna have my alternator checked at Discount Auto Parts.
I've never changed the alternator on a 300zx before, is it something I can do on a saturday or should I take it to the shop?
Thanks.