Alternator or battery?

[Bwana]

My GF was driving home from work and she said stuff started to dim, but the car was running fine. When she got home, she shut it off, and tried to restart it....nothing. Her seat belts dont move (auto belts), and he dome light comes on dimmly.

This happened before, she jumped it, and it has been fine since then (like 3 weeks ago).

Kinda stumped.

[Budfreak]

Originally Posted by Bwana

My GF was driving home from work and she said stuff started to dim, but the car was running fine. When she got home, she shut it off, and tried to restart it....nothing. Her seat belts dont move (auto belts), and he dome light comes on dimmly.

This happened before, she jumped it, and it has been fine since then (like 3 weeks ago).

Kinda stumped.

I had a pretty similar problem. Check the positive terminal on the battery for corrosion. Even if you don't see much, clean it anyway. Has happened to me twice now and a good cleaning fixes it right up.

[want-a-fast-svx]

when my alt went the only light that came on in the dash was the abs, however upon killing the battery the car was running like absolute crap... I mean like on 2 cylinders bad and then it finally died...So i would say if it was running ok but wouldnt start back up then its probably the battery or possibly a alt. that is starting to fail, maybe even some parasitic amperage draw...Or is the battery dirty? If you have a dvm you could check for voltage drop on the cables and the post. Just some suggestions...

[Bwana]

Problem is, im in Milwaukee for school, and she's at home in Chicago, so have to walk her through it all.

Thanks though, ill see if she can check the terminals for corrosion. (it is a 92 after all)

[Bwana]

Walked her through cleaning the battery, failed to start once, but a minute later it restarted and is showing no problems.

Letting it run for a while, then she's going to turn it off and see if it will restart. Hopefully it lasts her through the week until i can get a look at it.

[want-a-fast-svx]

Cool that could be a good sign of just the battery being dirty or on its way out...You could always have her go to an autozone and have them check the battery and alternator for free just to be sure. Just a suggestion...

[dannmarr]

Buy a volt meter that plugs into the cigarette lighter. This way she can keep an eye on the battery charge. This also helps to see if the alt is working properly. Around 12V with the ignition off and around 14V with the engine on.

[Bwana]

She went to Pepboys and got a new battery. Not sure if they checked the old one or the alternator or not though. They did say it was a really old battery though.

[Earthworm]

Sounds more like the alternator to me. I'm usually the one to suggest getting a voltmeter for the cigarette lighter.

Once running the car gets most of it's electrical power from the alternator.

[dannmarr]

You are correct Earthworm, you recommended the volt meter to me and it was one of the best things I have done! Thanks!