Battery light

Last night while driving home, my wife's 99, manual, had the battery light come on and off twice within a half mile stretch.

Is it safe to assume that this could be a failing alternator? She said there weren't any other issues other than the bat light coming on. The other day her aux fan stayed on for like 5 minutes after shutting the Jeep off, I'm assuming that could be a relay failing as well.

Not sure if the relay could trip the battery light or if they're two seperate problems.

You have the idiot light cluster? No voltmeter?

Sounds like the alternator output dropped so I should thingk maybe yes to your question.

But, as always, redo all of the grounds before you spend the bucks on a replacement component.

I would pop in a new relay for the fan just to eliminate it. Relays are relatively inexpesive but get one from either NAPA or the Dealer. It's a quality issue with the discount parts houses...

As the fleet ages you'll be seeing more and more alternators with worn out brushes. That's the likeliest cause for intermittent alternator failure. Eventually it gets worse, and the light will stay on. If you can catch it while the light is on, take a stick or a piece of pipe, and rap on the alternator while it's running (careful of moving parts of course). If the light goes right off, it's probably the brushes. If the slip rings aren't worn out, you can replace the brushes. Otherwise, it's time for another alternator.

Yea she's got the idiot lights in hers. Most basic model XJ there is... ex government vehicle with no bells, whistles or even a hint of creature comfort.

I was planning on upgrading her battery cables, so i'll either just do that or double check grounds and see what happens.

u can also put a multimeter to the alternator while the truck is on while running it should read 14 volts but i recommend cleaning the battery terminals my voltmeter was jumping up and down due to build up on the terminals cleaned those off and now im all good.

IC panels are relatively inexpensive, could swap it out with a few minutes time.