The only reason I use Autozone is because they can look up the warranty by your phone number. No need to carry a receipt.

Their rebuilt alternators seem to last between 1 and 2 years before going out. I've got half a mind to upgrade to a higher amp alternator and get away from my "lifetime" one.

 

I had a similar problem a couple of years ago. For me, all it was was the 12v wire a the back of the alternator was chaffing near the valve cover area. this wire is encased in a black plastic wire protector and it had worn through the protector and then through the wires insulation causing it to short out. Hope it is an easy fix for you!

 

So Chris, did they wife let you try her pink alternator (iirc). If so we need a pic. Any updates?

 

Sorry Grant. No updates. I left the truck parked today.

I like the idea of checking for chaffed wires, so I'll do that tomorrow. I also need to find a flat blade and a test lead I can use to ohm the plug on the alternator connector. I tried to do it yesterday holding the probe on a mini fuse stuck in the connector, but wiggling the wire and holding the probe on the back of the fuse proved to be beyond my capabilities.

I want to ohm the wires, for chaffing, then test drive to verify the condition still exists before swapping in the pink alternator.

 

On some of the plugs I use a piece of the stainless strips that attach the wiper refill to the blade.The hook alligator clip Pretty handy on some

Also check the wires where they cross over the alternator

 

one other thing you may want to try is just to move the wire and or the plug on the back of the alternator to see of the light goes out. If the wire is chaffing, or the connector is loose, the light may go out when they are moved a little. Might be a quick easy way to know where to start.

On some fords, there is a wire that goes from the ignition switch to the alternator. Not sure about these trucks, but if it does, a loose wire or connector at the ignition switch could also be your problem. It definately sounds like a wire or connector problem versus a battery or alt problem.

 

Well I pulled the trigger on a Vatozone alternator today. Light went out immediately. I am hoping that was my problem and that I won't be chasing down chaffed wires as well. I did notice the two little wires were getting worn from the big wire crossing over them and rubbing them. No bare wires that I could see, even down near the valley and valve covers.

 

Update: It's been fine until Wednesday night. Then the light came back on.

So I thought of Jim's advice, pulled over and wiggled the connector. Light went out and I continued home. Hit a bump and light came back on. Pulled over and used some electrical tape to hold the wires in the right spot. 300 miles later and the light still has not come back on. Guess it's time to get a new pigtail for the alternator plug.

 

Mine's been doing the same thing, Chris. But with big voltage swings (12.5 - 14.4V). Cleaned all connections, even replaced the pigtail at the alt since it looked dodgy. It was about $30. Still had the problem. Drove to FL with it like that & it took out my VSM. No power locks, key fob, auto lights, & the radio stays on when I shut the key off...... AZ says the Alt is good, but I'm taking it back down there tomorrow & demanding a new one if they say it's still good. Then I'll replace the VSM & have Ford program it. Not a happy camper....

 

Izzy

the light from what I understand comes on if the alternator is not turning on its field. which means is not putting out voltage. the 12ish volts you see if the residual back feed from the batteries. If you are going through multiple alternators you have a wiring issue. I would try to locate a Wiring diagram and trace it down.

I spent months trying to figure out why my mustang would not charge turns out there was a fusable link in the dash that kept the Alternator from turning on the field.

 

Dang Joe. I saw the pigtail online for $3.50. I need to find that link again.

I've got to help my daughter move this weekend, but I've got the same Autozoo alternator on my truck. Since they both have the same warranty, if you want to drive South this weekend and swap alternators, maybe that will help you narrow down your issue.

 

I can add a little to this discussion. This summer on vacation, I was tooling along I-29 and my A/C cut out started blowing hot air. Looked down and the battery light was on. Pulled into the Ford dealership in Maryville, MO. They ran codes and told me the alternator was bad. I had the alternator replaced, then lo and behold, the A/C started working again. A week later, I had to replace both batteries. The end of the story is that I have traveled a month and a half from that point with no issues. I would definitely say you probably have a grounding issue, especially if you hooked up the jumpers and the voltage increased. Just my two cents.

 

This sounds all to familiar... When I bought my truck in Feb 08, it was dead on the lot. They found the alternator was not charging & put on a new one. Last October, I started having charging issues again so I took it back where I bought it & they replaced it ( I found out they previously put on a Napa rebuilt & got this one replaced under warranty) They also changed one of the batteries. Well, on the way home from camping on the 4th of July, it was pretty hot & the 1st time I used my A/C this year & once again.. my battery light came on. This time, i was thinking the problem was the A/C. causing some kind of electrical issue.. I used Springer Pop's write up & adjusted the airgap, hoping that would solve the problem, but it didn't. So I went straight to Napa & they warrantied my alternator & all seemed good.. until a month later...yep, once again.. alternator light.. I took it back & they tested it.. said it was putting out something like 12 volts, so the gave me a new one & so far so good... But this is my 4th Napa rebuilt in 2 1/2 years.. I was chocking it up to just "cheap" alternators, but maybe I have an issue too... I did check the grounds on the block & they all seemed tight & were pretty clean.. I guess its time to look for loose/chaffed wires as well.

 

when checking grounds make sure to check them with a ohm meter or a multimeter in the Ohm setting. Isolate the cables test them end to end. You should see around .6 on a good cable. if you have anything over 5 ohms replace it.

 

Mine is still working with the tie wrap that I installed coming back from TN. I have to replace the pig tail as well.

Always always replace the batteries in pairs.