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Ford battery light on when idling

Battery warning light came on a couple of times when driving to work in my 2000 F-150. I had thought that the instrument lights had looked dim for a couple of days. The warning light was only when the truck was idling and the warning went off as the truck was moving.

Have your alternator tested. Battery too, while you’re at it.

Battery is less than a year old.

Batteries, like any other part, can be bad off the shelf, Bill. New does not = good. Get the battery and charging system thoroughly tested.

And I wouldn’t be surprised if the belt tensioner was weak.

Low idle ?

theres a chance you need a new belt, the belt might be slipping on the pulley.

Truck now towed to the shop. While driving home last night, instrument panel stopped working, headlights dimmed; the lower the rpm, lower the power. Pulled over. Truck would not restart. Battery would charge with a jump, but not keep the charge. Now just hoping for good repair and cheap bill! Will let you want the mechanic says. Thanks for all the input.

$500 later we had the Altinator and Serpentine belt replaced. Running fun now. Thanks everyone for the input.

Well, I figured it was the alternator but wouldn’t be happy about the $500.