Batter light comes on intermittently.

I searched around the forums before posting and found a few possibilities but nothing specific to my problem. I hope someone here has heard of this . I have a 1999 Ford
Ranger, not too many miles for its age. While driving I noticed that the battery light came one and the voltage meter dropped down, not to low but just above the bottom bar. I had a shop check the battery and alternator, both checked out fine. It was one of those little hand held units so I honestly don't know how complete the test was. The tech thought it might be the belt so I replaced it yesterday. The batter light still comes one. When I had the belt off I noticed that the pulley for the alternator was shiny while all of the others are a little dark. I don't know if it was always that but it looks like the belt might have been slipping. I should mention that when I changed the belt I thought it was very easy to move the tension pulley, easier than I thought it would be.

When I'm driving the light will stay on for about 30 minutes, along with the lower bar on the meter but all of a sudden the light will turn off and the bar will go back up. The light went off on a hill but sometimes when I'm driving on flat pavement. I also noticed that when the lights are on the meter bar drops. When the tech tested the batter and alternator he had me turn the lights on but that didn't cause the meter to move.

Some have said I have a bad alternator or voltage regulator. I want a second opinion before I take it to the shop or shell out for a new alternator. Could it be the belt tensioner? Is this a common problem with Rangers?

Just want to check around.

Thanks.

Think mine is starting to do same thing. Mine will only lose voltage when slowing down to a stop sign or stop light. It seems to do it more in the cold. I have even lost power steering when turning at slow speeds a few times. I can hear what seems to sound like a pully slipping or bearing going out. When I accelerate voltage returns and stays normal. Like you I'm leaning toward a bad belt tensioner. I do have a new alternator. Have you had any luck??

By far the cheapest way to go is to replace the tensioner first. I had the same problem on my F-150 (5.0 V8). If after you replace the tensioner you still have a problem, swap out the alternator with a reman (or new if you're rich). But I think the tensioner is the source of your problem. Now to the guy who lost power steering at low speeds: Your problem is def the tensioner. My dad's Bronco (351 Windsor) did the same thing. A trip to the salvage yard and 15 bucks later, all was good. Hope this helps.

Yes... It was the belt tensioner, thats what I thought it was. I just wanted a 2nd opinion.
Thanks....

Before you either buy or pull a tensioner, try tightening the one you have by using a 1/2" socket in the lower opening of the tensioner. I just tightened mine a quarter turn and that fixed the problem as well.