Hey all, I'm sure this post has been started before for similar problems however I was unable to find the solution in previous searches... It starts just like most all alternator issues, heading home from a long day at work at night and then a noticeable decrease in lamp outputs, voltage meter on the dash is showing below half and about 30 minutes later dead battery. Got a tow home and charged the battery overnight, battery took a charge so NOT the battery. (Also ended up getting a brand new one to be sure) So a $100 battery later, same thing happens. MUST BE THE ALTERNATOR!?!!?

Brought my alternator into an auto zone to be tested, PASSED! What the hell, measures between 13-15v, well ok then. Must be the cable from the alternator to the battery!! Ran my own tests too with a multimeter to be sure. The alternator post is putting out north of 13v pretty consistently however it doesn't reach the battery. I read something about linkable fuse wires but couldn't locate it... so I ran my own 8 gauge wire from the alternator post to the battery, STILL NO CHARGE (12.2v)!! How could that be?? The alternator is putting out the current but it just doesn't wanna jump into the damn wire?? It has me baffled and hoping someone could shed some more light on this. Maybe a grounding issue?? I cleaned all terminals and checked most common problems. It's not a fuse issue since the alternator is putting out current... saw it with me own eyes! And I'm pretty sure it's not the voltage regulator since... well since the alternator does actually work. Any help would be GREATLY appreciated. In the meantime i'll be twiddling thumbs and calling out of work! Thanks in advance!!

 

I would check wires and look for a good ground. How old is the alternator ? I would not assume an old alternator is good from a simple test... but check ground first.

 

Did you ever find out what the problem was? I'm going through the same thing right now with a 05 lariat

 

Sure sounds like a bad alternator to me.