The battery light comes on occassionally. Sometimes it's not on long sometimes it is. Once it stayed on long the battery gauge went to L and the engine eventually died. I jumped started the truck ('02 F150 Super Crew 4.6) and was fine for the rest of the trip. Battery has never been low at start. Always works starts fine.

 

If the battery is not very old, probably the altenator. I would get it checked. It will kill the battery eventually.

 

I had both the battery and the alternator tested and they both tested good.

 

Then you have a bad connection somewhere. Most likely down under @ the starter. Take a look.

 

would you happen to know when it has charging issues? under load, at idle, etc? my roommates v6 mustang once again blew up his new(5 weeks old) alternator from advance auto. this time it wouldnt charge when he gave it gas but it still passed when he had it tested. this is the 7th one he's put on his car, all are from advance because they keep getting warrantied. is the alternator original? definately check the starter as jbrew has said.

 

Yea, honestly - In my experience, the only problem I've seen cause that light is the Alternator. The brushes sticking in the regulator (from dirt/sand grains)and/or cable getting way to hot.

The problems intermittent, so the alternator could pass tests and there could still be a problem with it.

 

I had a 98 f150 that had a loose fuse you could wiggle in the cab by the hood pop.When ever the light would come on and the meter would go down i'd wiggle the fuse and the needle went back up,Just maybe?

 

Alternator is on it's way out.

Phil

 

most likely the alternator.

check all connections though, cant hurt. might even find something else that might cause trouble. have you any kind of high pitched whirring noise or whine?

 

I appreciate all your responses. I will check the connection at the starter first. I will also check the fuse next time the light comes on. I have not heard any type of unusual noise from anywhere under the hood. There is no particular time or circumstance that accompanies the light. It just seems to appear sometimes at start up. Sometimes during flat level cruise. Then it just goes away. After I check the connection and fuse I will post the results.

 

yea. mine too, but mines a loose connection I cannot find. I go over bumps and it comes on and off. . . grr

 

Since I had the Alternator and Battery tested the light has not been back on. I have put on about 1000 miles since then. The weather has warmed some. I don't know if that is a factor or not.

 

+1 alternator When mine went out the light started coming on at higher rpms, and then it started coming on at lower and lower rpms until one day I just made it home on the battery alone.

 

Just before my original post the light came on and stayed on. I ran for about 30 miles on battery alone. It finally gave out. All gauges gave out then the engine died. I jumped it with another car and it has been running fine since. The light just came back on yesterday for the first time in over a week and only stayed on for a couple minutes. I have not had a chance to check the connection at the starter. I will in about an hour and keep an eye on the light.

 

Pull the regulator and check the brushes - Somethings going on. Make sure BOTH are working, Looks like this -



One of those may be jammed or sticking.