Battery light on at low rpm

[snowman]

2003 ex 7.3 psd battery light comes on and off, replaced alternater 2nd one in 6 months (napa) and batteries, Meter shows charging on the batteries and the output of the alt, but light still on mostly at low rpms, any ideas besides a short some where

[Diezel Dawg]

Alternators from the part stores are known to be bad shortly after buying them. Sometimes the alternators will put out, and sometimes they wont. usually a bad regulator. they can really mess with your mind. i say replace it and take it back and get a new one under warranty

[Type 2 Sniffer]

Check your fuses (if you already haven't). Can't remember which one, but after jumping a guy, I blew a fuse and a while later had the same issue. Worth a shot as it is a cheap fix. Hope it helps.

[jbeasts10]

I just went through this exact same thing 2 weeks ago.My light would flicker at low rpms,so I replaced it with a new motorcraft from the dealer.As soon as I started the truck the light was on all the time and wouldnt go out.I went to a local alt shop and turns out the internal regulator was bad(New Motorcraft Alt).With the truck running unplug the little plug on top of the alt.If the light goes out its your alternator.Hope this helps.

[cchase]

i say replace the alt. again

[Ryan Rønning]

I had this basic problem about two years ago and it was my Alternator!

[ford_trck]

Check your batteries too. My neighbor had 1 bad battery and it fixed his light.

[snowman]

1 battery is about six months old when I replaced the alt. the first time, and the other battery is brand new with a 2nd alt, still running with the light on and according to my meter when you unlug the pug on the alt the batteries read lower volts, realized this morning that my trailer plug wires are out so I'm thinking short. thanks For all the info. snowman

[snowman]

Ok here's the latest cleaned all terminals and battery light went out, then on the way home from work, battery light back on then engine dies. Each battery has more then 12 volts and engine cranks but will not start, checked all connections and still no start. Was able to coast it into the driveway any ideas????????

[snowman]

Well wife started the ex today after sitting all night, runs with battery light on again