Battery light is on

[exbass94]

The battery light on my Explorer lit up today. I took it for a short drive (about 2.5-3 miles round trip) and the light was on the whole time. I had to pick up my uncle's mail while he's away on vacation. When I got to his house, I turned the truck off and re-started it, hoping that it would disappear. It didn't.

When I got home, I took the battery cables off and cleaned all the corrosion off them, hoping that would fix it. Again, it didn't. The voltage gauge on the dash is right where it should be, and my multimeter is showing a good 14V across the terminals while the engine is running. The battery is showing about 12.75V with the engine off.

The battery is about 6 years old with 36k miles on it, and the alternator is factory original. Should I just go ahead and replace both, or should I do a little more diagnostic work first?

EDIT: Forgot to add, my belt tensioner is really old, pretty likely original too. Probably should have changed it when I did the serp belt a month ago. It doesn't appear to be slipping (no noises or anything) but maybe it is and it's not letting the alternator charge up?

 

[Mac]

Always cheaper to check for a problem than to throw money at it and hope it goes away.
Dave

 

[exbass94]

I know. What I meant to say is, what else can I check, and HOW do I check it?

 

[Toms01PSD]

I had the same problem. Check the single wire connection on the side of the alternator next to the 4 wire plug. The clip was broke on mine and it disconnected itself and triggered the battery light to come on. I wrapped some electrical tape around it so it was nice and snuck in the slot and I haven't had a problem since. If you need a picture just ask.

 

[exbass94]

I had the same problem. Check the single wire connection on the side of the alternator next to the 4 wire plug. The clip was broke on mine and it disconnected itself and triggered the battery light to come on. I wrapped some electrical tape around it so it was nice and snuck in the slot and I haven't had a problem since. If you need a picture just ask.

Yup, I just fixed it before I even read your post. But, you're right it was the single wire. Mine wasn't disconnected, it was just corroded. I cleaned it up and reconnected it and the light is off.

 

[Toms01PSD]

Yup, I just fixed it before I even read your post. But, you're right it was the single wire. Mine wasn't disconnected, it was just corroded. I cleaned it up and reconnected it and the light is off.

Glad to hear it.