My battery light was flickering with no rhyme or rhythm. I went and had it tested and everything was good, charging at 14.whatever, but across the little code thing it said that an interior light wasn't turning off, or something like that, but I have searched my truck and can find nothing. Then it won't happen for a few days, and then it will come back. The battery hasn't changed at all so far and I replaced the alternator a few months ago and everything with that is fine. Any ideas? Thx.

 

Nobody has ever had this?

 

My truck had something similar about two or three years ago. It lit the battery light a couple of times until finally start showing the charging needle on the low side.

Test the battery and alternator and everything was fine. Bought a new battery and the samething the next day. Then bought a new alternator and problem solved. I just did this because I bought my 99 F-150 in 2003 and 85000 miles. So not knowing the history of the vehicle I just get those new and out of the way along with a new serpentine belt and at end got my problem solved. If you are sure that your alternator is good then that could be other problem.

Said you changed the alternator sometime ago????...........Check it again.... could be a loose conection on previous instalation.

Good Luck

 

whats the condition of the belt? is it slipping once and a while.

 

I had the same problem, it would tend to flicker on and off more at higher rmp's, it ended up being the alternator.

 

Mine is doing the same thing. Comes on when I first start it. Measure the voltage 11.98. All it takes is to rev the engine and it goes off. Measure the voltage and it's 14.3-14.5.

Does a new alternator come with the pulley on?

 

The internal voltage regulator is gone. Now you could replace that regulator, however I do not recommend it. Get a new or rebuilt alternator as the bearings, brushes and other stuff may soon go south also. The alternators do come with the pully and fan but these may need to be replaced with the old one to fit the belt style you have.

I go a rebuilt 130 amp alternator a few years and i cost me $125.00. But it is an easy replacement if your hany with tools.

Good luck

 

Well I changed the alternator a few months ago with one from O'Reilly's. If I remember right - it has a lifetime warranty? But at this point, the battery light is not giving off a bad alternator code, but that an interior light is remaining on, but I can find nothing.

 

How will I know if the belt is slipping? I am still having the same problem a few weeks later and the battery is still holding its charge, but that light still comes on at different times, sometimes flickering, sometimes it stays on solid for a short time. Could it be the belt? Thx.

 

I went to AutoBone and had the battery and alternator tested and everything came back fine, even tho the battery light is still flickering on and off. They had no help for me since it was giving them no info and everything checked out fine. They even said the belt appears to be tight and good.

 

Bad Voltage Regulator by the way. New alternator fixed it right up. Thank goodness for that lifetime warranty.