Are there any other things to check on my own before paying the piper again? The battery lite does go off sometimes but always comes back on. Most of the posts in the archives indicated the alternator but mine is fairly recent and tests well. I have two new Optima batts that also test out perfectly.

 

Alternator belt being too loose will cause this.

 

also check the quick connect plug on the top of the alt. sometimes they work loose and don't make a positive contact. A replacement plug is avail from most auto parts stores.

 

The 2 small wires coming off the same quick disconnect plug will sometimes rub on the altenator housing, down about 1&1/2" from the connector.. My battery lite was coming on and going off and the green wire rubbed thru the insulation.. It was very hard to see.. Had to use a magnifying glass to see the bare copper.. These wires are abit too short coming out of the wire harness.. Reinsulated the wires and it has been good ever since..
Also, check the main wire harness that goes over the driver side valve cover.. These will also rub causing shorts.. Take a mirror and look under the wire harness..

 

Did they test the voltage regulator on the Alternator? I got a bran new NAPA Alternator that came with a bad voltage regulator. They said it tested fine until I described my problem then they tested the regulator and found it was faulty. Right out of the box. Just my .02

 

Thank you all for the replies. I am glad its likely not anything expensive. Just owning and driving one of these anymore is tough enough.

 

Let us know what you find.. It nice to know what causes some of these problems..

 

It would be nice to know. I have not noticed any damage to wiring anywhere just yet. And the battery light has stayed off for the most part the last two days getting slammed at work. So, God willing, it stay off. Elec. probs make me nervous though. I got stuck out in the bush in Alaska once for two days in a Dodge Powerwagon replacing wires until I finally sprang for a new harness.

 

I wise man here once said something to the effect of: "Automobiles don't fix themselves." Keep an eye out, the problem will return. I can almost guarantee it.

 

I have always turned off the batt lite before just changing out the batts or alternator. I may just get rid of my Duralast and get a Motorcraft when I can. The price diff between the two was huge. They say it all tests out though.

 

yeah, I have a draw on my batteries, cause the truck will stil for two or more days and NOT start. very frustrating. so I throw on the charger when I need to take the truck.

 

Bringing this post back up becuase it is exactly what I am going through. Alt is one year old, batts are 6 months old motorcraft. Batts test good, alt is putting out 14.4, with everything turned on. I have my ohm meter out and am wandering if I can check the voltage regulator in the Alt while it is on the truck? I started another post a while back after I noticed my lights dimming while driving, now I am actually getting the flickering batt light. Also, I have tugged on the serp belt between the alt and top pulley and I can pull the belt up about 1/2 inch, seems tight. Idler tesion is tight.

 

there are fusible links between the Alt and batts also check the main grounds on the front of the block. There is one of the wires light green red stripe i think that goes directly from the alt to the cluster that drives the light. it goes through 2 connectors getting there. the first is the main one over the valve cover the other is either the top or middle connector in the row of 3 just inboard of the pcm connector.

PM me with your email an ill send ya the wiring diagram

 

MTDemX - check the glove box light and the underhood light, maybe just pull the bulbs, and see if you still have a drain. They are two fairly common problems, and you won't see the light if it is stuck on (and it will kill the battery), plus it is an easy thing to check.

pullinair - it is difficult to check the regulator while on the truck - the good old days of "full fielding" an alternator are gone. But, if you are putting out 14.4 with everything on, your alt is where it should be. Do like amiller93 says above - check the harness.

Alan - only guy I know can rattle wire colors and pin positions off the top of his head - just toooooo sharp!!

 

Green Wire with red stripe was laying on the alt rubbing. It was actually making an indentation on the alt (shiny spot) were it was rubbing. Moved it away from the alt, taped it and so far I have no batt light/ head lights dimming anymore. I think this was the prob. It must have been grounding out there through a small rub through, too cold today to get an upclose on the wire but it was black/burnt where it was laying on the alternator. Tonight I drove it and not one time did the head lights fade. Must have been a microscopic rub through. Thanks Alan.