charging system problem

[adrenalinejunky]

out plowing the other night lights went dim batteries obviously not charging. Tested and they said alt. is charging, replace regulator. Replaced and still no charge. Checked all fuses, checked all wiring from alt to regulator, checked all connections.
Withthe tester we have the volts are staying at 12.1 after charging batteries up to 13.5. When light are turned on goes to 11.8 volts.
Calling for snow Monday-Tues. and truck is a must for salting the accounts. Any help would be great!!!

[mschn99]

sounds like a bad alt to me...check all your fuses first...

[adrenalinejunky]

Sorry didn't mention that I did replace the alt. today also even though the other one was only 6 weeks old. Call the employee that was driving the truck most of the week and he said the volt guage was jumping from middle to pegged the how week, fail to mention that to myself or the boss:handguns: :nono:
I have checked every fuse I could find.
I was told tonight that there is a wire that runs off the alt. to starter that starts single, splits then comes back together as one, done for voltage/watts/OHMs or something and that wire goes bad all the time???