Battery Light (1 Viewer)

[ivancook]

Battery light has been coming on intermittently. Once or twice a day it comes on and stays lit for a few minutes before going off. I found a loose connection where the alternate cable runs to the battery, but have fixed that and it is still happening. Other than the fuses there, any other ideas what to check. The voltage gauge on the dash typically sits one mark down (14.5v ?) from the top (marked 18v), but when the battery light comes on, the voltage shows to be going higher via that gauge.

Could this be a sign of the alternator failing or do they just usually go out completely? Any chance an old battery going out would cause the same symptoms?

 

[badlander]

My battery light came on and the alternator was the culprit. Voltage was up there with no lights or accessories on but as soon as I hit the lights - down went the volts. Good thing I have dual batteries as I had to drive about 40 minutes home from my dads in the dark on I75. Ran on running lights only. Had the alternator tested by 2 places and both said GOOD!, 14.8v's. But the second guy said the testers only check the voltage and NOT amperage. Turns out mine wasn't putting out enough amperage to run the accessories due to 1 burned up brush. I put in a replacement alternator and it's been good ever since. Rebuilt the old one for a trail spare.
Warning - I had to wait for a week for the new one. Had to get rides to work and back, a real pain. No one had them in stock here. It shipped ground from California. So, If you think yours may be waning, order one now, don't wait, or at least check local availability.
FYI, mine quit at 167K miles.

 

[ivancook]

badlander - was your battery warning light coming on and off, or was it staying lit when the alternator failed?

 

[Travis351]

Can you get the light to turn off with aggressive acceleration?

 

[ivancook]

So far it seems to go off on it's own after a few minutes. Doesn't seem connected to acceleration.

 

[Travis351]

Fwiw When my alternator was failing, I could get intermittent charging and battery light off by increasing rpm.

 

[Sandroad]

To partly answer one question; a failing battery can cause voltage fluctuations. However, your symptoms suggest the light is coming on with too high a voltage? If the battery is old (and the connections are all good), you might try replacing that anyway before you do the alternator.

 

[2001LC]

Make sure battery posts are clean and greased, and that serpentine belt, idler pulley (clue: sound) and tensioner are all to spec. If that's all good, have battery and alternator checked, I think Wal-Mart, and most parts stores will check for free.

Tip: Unusual, loud or oscillating sound of from alternator bushing and pulley's bearings can give clues as to condition.

 

[ivancook]

Thanks for all the suggestions. I'm not sure what the problem is/was but I just drove from Pagosa Springs to Austin and the light never came back on. I checked connections to the battery posts, fuses, and belts and everything seemed fine.

 

[badlander]

My battery light came on and stayed on probably because I had the AC on because my dad was in the car with me. Then when I left his house to head home it was getting dark and then it was all bad news from there. Made it home though......barely.