Ford F150 - Battery Light on, Gage shows OK.

91 F150---- Battery light came on recently but the gage shows normal charge. I also have an aftermarket Battery gage, and it shows charge. --I've never seen a battery light on with gages showing correct voltage.

Any ideas?

Thanks.

Is is a sealed battery or one where you can service it with distilled water?
Is there an indicator on the battery itself (usually a small glowing LED that shows whether its good or bad)?
What type of gauge do you have installed?

The battery can be showing approx. 12V but there could be a problem with it accepting a charge or holding it. Are you checking that gauge with the truck running? Try throwing a mulimeter on the battery and see what it is showing.

Unlike the CEL that we all know and love, the battery light tells us little. I'm not an expert but know that one or more components of the charging system and other components with loose or faulty connections could be at fault. As Vampkiller says, first check the basics; terminals for corrosion, belt tension and alternator output. These checks will determine that the battery can get/is getting a charge. The last test (load test) will tell if the battery can hold a charge. Either AutoZone or Advance can and will do all of these tests for free. I'd be interested if any of the senior members could shed some light on the "idiot" light for the battery. What component/sensor is responsible for tripping this and under what conditions is it set? Hope this helps.
Willy

Guys, the (sealed) battery is relatively new. Battery test gage shows full charge. Aftermarket gage is an Autometer. At around 1000 rpms or so it reads 14 volts, so the alternator is doing it's job. The in dash gage lays over to about the 14 volt area. Nothing shows discharge, and all is well running/starting wise. -- I'm pretty savy on mechanical stuff, build engines, do body work, electrical, etc, but I've never seen an idiot light on when all else seems normal. ---I don't run the truck much, and I'm thinking that it's possible that a mouse may have chewed a wire or something. -- I'm not sure how that light is grounded.----As soon as I get time I'll at least start pulling fuses and see if I happen to hit a circuit that changes things.

I'm tending to agree with your assumptions. If all other tests and indications are normal, it sounds like that battery indicator lamp is getting a short to ground. I'd go the play it safe route and check it routinely for the next while and make sure you still get normal indications all the time. If it stays all good then it's obviously just that light.

Then you can fix it, pull the bulb, or put a piece of black tape over it!

Ten four Vampy! Really not much need to have a light and a gage at the same time. --But this will bug me untill I figure out the "Why" its on thing. Once the weather warms I'll get serious about looking for the cause.

Take care!