The battery light in my '99 Ranger XLT (3.0L, 2WD) recently began flickering during driving and even stays lit completely sometimes. Anyone have any guess what it's trying to tell me? I checked battery voltage with the key off (12V) and with the car running (14V), so I'm not sure what's going on. Maybe a loose cable somewhere? I could swear that the door windows and the wipers seem to be operating just a bit slower, but maybe it's just me. The battery in the truck is the original battery, 128,000 miles, and the alternator is original.
Probably about time for an upgrade. Just 'cause it's 12 when not running and 14 when running doesn't mean it's in great shape. My suggestion would be to go ahead and replace it with another one. If it's anything like my replacement, the battery was small anyways. Wouldn't say there was a rush though, just when you get the chance.
A fully charged battery should read more than 12 volts. Have you checked the battery electrolite level lately????
Shorting battery cells from vibration whle driving, could do it.
A weak belt tensioner could be allowing the belt to slip some while driving.
Bad alternator slip ring brushes could do it.
Loose or corroded battery cables, as you mentioned, could do it.
So it could be a number of things.
If your not into turning your own wrenches or troubleshooting electrical problems, why not run this puppy by your favorite autoparts store, for a no cost in vehicle electrical system check up, via their portable electrical system tester.
It can properly load test the alternator, battery & cables & will likely be able to pinpoint your problem.
I drove the truck over to Autozone tonight to have the electrical system tested and the truck died on the way home. While I was at the store, the guy ran a test on the alternator and battery with the truck running - alternator was putting out 11V, battery voltage was 10V or so and dropping rapidly. I kept the truck running - fearing I had little juice left in the battery - and sure enough I only made it another 1-2 miles before the ABS light, brake light and check engine light came on, and then finally, the engine died.
I'm just wondering if the alternator is bad conclusively, or if maybe the battery is on its way out. I'm charging the battery overnight and I'm going to have it tested at a shop tomorrow to see if it's bad or not. I figure if the battery is good and it loses juice again - because the alternator is shot and not charging - then I'm pretty zeroed in on the problem.
Actually, I set the charger to fast charge overnight - wasn't sure which setting to use or if it mattered all that much - so will that be safe until around 7 a.m. tomorrow morning when I get to it? I hope so, although the battery is at a garage about three blocks from here (but don't feel like going and changing the setting at this hour if I don't have to!)
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