I have a 97 ford ranger. About a week or 2 ago my battery light would flicker or flash on and off once in a while. I went to get the battery checked and alternator. According to their tests, the alternator is fine. The battery was over 7 years old, and since batteries usually last 3 to 4 years, we figured the cells were going bad. I replaced the battery and still the battery light would flicker.

I talked to a few people and we figure its a loose cable or the serpentine belt might run through the alternator and if it is slipping, it might cause it. From what i can tell none of the cables are loose, the ground cable and the battery cables seem to be on tightly. I had the serpentine belt replaced.

The last few days i havent seen it flash or flicker on, thinking it was good to go. but this morning it did it again. It flashed on for a second and went back off.

My question is, what else could be causing the light to flash/flicker on?

Thank you for your time.
The serpentine belt was a few years old, so figured it was time to be changed as well. I know its been at least 3 years since it was changed since i moved back to NC.

When i was looking at the cables, i didnt see any problems with them. No corrosion from the battery (did have a problem with old battery that destroyed the end of a cable) but i didnt look for marks where a rat or something may have chewed of them, i will double check for that. I will have to look into the RPM as well. the truck has sound different but i will look into as well.

I havent jumped anyone car with my truck since i have had it.

The truck starts up fine with out any problems. My guess is that it is a loose wire somewhere causing it to light up, but like to make sure. This truck is the only thing i have for transportation and cannot afford to it to break down.
Correction to above...the truck hasnt sound different while its idle or starting up, or anything. Its sounded the same.

Hi,

A loose belt will probably squeak, not cause the alternator to stop charging intermittently.

I had my alternator battery light flash when I had the battery voltage up to 14.4 volts, but it stopped when I shut off my solar system (on a Ford Motorhome).

You should check the battery voltage. Driving down the road it should be reading about 13.5 volts +/- 0.5 volts. At rest the battery if it is full should be 12.7 to 12.8 volts, and if you turn on the headlights it should not fall by more than 0.4 volts.

With the engine running, at idle, if you turn on the headlights, the votlage should stay the same, perhaps drop 0.1 - 0.2 volts but not more than that. Sometimes the turn indicators will cause a slight voltage loss when they are flashign on. If the battery light is flashing on and off with the turn sinals or emergency flashers, it can indicate a alternator that might need replacement soon, but it is also something I would not let worry me.

If you do someone a favor, and use your car to jump start theirs, shut off your engine while they crank over their car. Your alternator is not required to start their vehicle, your battery will provide plenty of power, yet the alternator will go into the full capacity charge mode, and can melt the diodes inside the alternator while this is happening.

If you have been jump starting cars recently, you might need to replace the alternator. You can get them cheap at most junk yards. It does not have to be from a Ford Ranger, the alternator from another Ford product should fit. Look at the same size engine, such as a minivan, or small sedan. If the mounting brackets look the same, then it should fit, but be careful when measuring and compare it to your current one at home, if the belt mounting location is farther from the tabs, and not an exact fit, the belt will not line up correctly.

It hurts me to see a fellow Ford Ranger owner with a probo....

Let's see....
cables (check)
serpentine belt (check)
alternator (check)
battery (check)

what bout, RPM? Is ur RPM constant? This may cause the alternator charging method to be interupted...
Also, how bout the regulator of the alternator? Did ur mechanics check that?

Yer cables are tightened well... tightly... but what bout the conditions of your cables? Maybe it's the work of a mischievious rat? A few nibbles? Ur cables may still be in contact... but well... depends cux, Ford Rangers start off pretty rigidly and that may cause the nibbled cable to lose contact with each other.

It's normal for an older car. It's probably just a wiring problem. My car does it when I'm all the way on the gas. Don't know why. It's not like the battery is driving the car. As long as your car is starting fine and your electronics work, don't worry about it. You did what you needed to do to check up on it.