Kinda weird problem here, looking for a little guidance on where to start. The alternator went bad in my 98, symptoms were: at times the gauge would go to half of where it was normally and lights etc would dim, it would stay this way for a while and then go back to normal. Had to drive it one day like this just to get to work and back. Next day, new alternator gets put on. Volt gauge is rock steady, has not moved at all. Drove it around town all day the first day, everything is fine. Now I have driven it to work two days(~ an hour each way) and the Batt light is going on and off.

Now what can cause the Batt light to seemingly randomly go on and off yet the volt gauge stay steady? And I know the gauge was responding with the old alt, it would show when it was not charging full perfectly. Now it acts like it is charging fine, but the batt light goes on and off

 

Check the little wire that plugs into the back of the alt. Its all alone on its own plug.

 

what brand alternator? at work, parts has done given me the wrong alternator (fits perfect, everything plugs up) but for different application, and it does this. or possible faulty alt. hope this helps

 

I had a battery light driving me crazy and it ended up being the harness plug where the engine plugs in. A pin was bent over.

 

Hey y'all...Ive been stranded now 2wks..
​​We replaced both, the alt & battery twice...Along with a new Serp belt, batt terms & cables & installed another fan blade from salvage...Battery still putting out, alt is not & ive got a persistent batt light on dash & batt gauge showing Low voltage....Ive checked fuses & connections...everything getting DC on the meter... What's going on with her Truckness... 99 Ford Ranger 3.0 L v6 Single cab 2wd Automatic