I figured I'd try here since not too many people post in the electrical forum. Or maybe it's that no one has any idea what's causing my problem.

My brother has a '98 XLT 4x4 ext. cab with the 5.4. His battery light has been coming on and staying on lately. We tested his battery and a couple of the cells were dead, so we went and got a new one. The light is still on!
Is there a way to reset the light or something?
Does anybody have any ideas of what the problem could be?
He has a radar dector and CB plugged in to the cig. lighters, but they are not always on, and rarely on together. He also has a system, but it has been the same for over 2 years, so we don't think that is the problem. The light os on wether the accesories are on or not. The light will sometimes go off for a few seconds, but then come right back on. The battery guage is reading fine and everything seems to be operating normally. His alternator is also fairly new.
He does have the common problem with the AC blowing through the defroster, but I doubt that has anything to do with it.
We're stumped.

 

get a real volt meter and check the volts with the engine running, 14.5 about normal. if the volts are about that, then check the plug on the alternator.

 

I think beckerjs is on the right track....sounds like the alternator may be going bad.....

 

Hmm... That would suck for him because the alternator was replaced within the last 2 years. But we'll start there when he gets home from work. We're also going to check all his stereo wiring to make sure everything is connected and grounded properly. I'll report back.

 

Also, you might want to check for any corrosion on the battery terminals and/or cables...at the starter and battery.

 

GO CARDS