since a couple months ago my trucks volt meter would go to the second line then when charging to a little over half, but would only charge for about 5minutes out a 30minute average drive. Recently it would charge for about 2-3minutes out of the same 30min drive, 2 days ago it stoped charging. I replaced the alternator after it failed a test at 2auto zones (double checked with these guy's) new alternator is charging when tested at auto zone (no funds 4 NAPA) however my truck is not, what else can be the problem??

Oh and the new alternator fixed my jumpy tach now it's smooth from idle to wide open and back.

 

Check the body ground on the core support by the battery. If it's good, replace the voltage regulator. Genuine OEM Mopar units out of the junkyard are better than aftermarket replacements. Any old Mopar product will have the regulator you want. Get a couple, they are cheap.

 

thanks Wannadiesel