95 Infiniti J30T Brake Light & Battery Light Staying On

[badavis711]

I have a 1995 Infiniti J30T and ever since yesterday morning my brake light and battery light have both stayed on. When I come to a complete stop, both lights go off and as soon as I let off of the brake pedal, both lights come back on at the same time. My battery is fairly new and my emergency brake is not on, what could this be? Everything I have researched points to my alternator going out...could there be any other options?

[Q451990]

to NICO!

I suspect it's a bad alternator... your best bet is to measure the voltage at your battery's terminals. If you don't have one, you can get a cheap multi-meter at Harbor Freight, Walmart, etc. The $10 or so model will be fine for this...

Anyhow, you should be seeing about 12.5VDC with the car off, and about 14.4VDC with it running at idle, no lights or accessories on. Post up some results and we can go from there.

Heath

[badavis711]

I took it to Advanced Auto so they could measure the voltage on the battery and alternator and he told me that my alternator was overcharging my battery, that it read 18.6 volts and should be between 13.6-14.6. Said Thani would need to replace battery. This is the only vehicle I have. Will it be okay to drive it to and from work just tomorrow?

[Q451990]

Depends on what you mean by OK... If you mean, will it explode and leave your lifeless body hanging from a tree, probably not. Will it possibly cause the battery to boil over spilling battery acid into your engine bay, very likely. Worst case scenario, I'd take a box or two of baking soda and a jug of water to rinse it down with and use the soda to neutralize the acid as much as possible if it leaks out.

Heath

[fourdrinie]

youre better off replacing the alternator asap...then re-check the battery for overload damage

[EriCCirE]

Measure it yourself. I do not trust the guys at any of the autoshops.

I brought my hi amp alternator for them to test before I installed, and they said it was bad.

I played along and said ok grab me a new one off the shelf. When he brought it down to the counter I got all ready to pay, and then said, "why dont we test this guy to make sure shes good."

As you all are guessing, the machine said the new alternator was bad.

[Q451990]

Ditto on that... but I would hope that their machine could at least check voltage? I'd never trust their diagnosis on an internal part of the alternator though.

Heath