so i have 2 trucks in our fleet with the same issue, one is a 2011 the other a 2012, F350s both with 6.2 gas engines. the symptoms in both are the same or very similar, my company truck is one of them. one day while driving the battery light came on, it wasnt charging fully so i replaced the alternator. still not fully charging and battery light is still on. its charging around 13.6/13.8 but rapidly fluctuates above 14 and below 13. at night the headlights will go a little dim then back to normal, constantly. i checked and cleaned battery connections, fuseable link connections, power and ground at the starter and any other grounds i could find. i even replaced the alternator again just in case.i didnt think that was it anyway since i swapped out the alternator in the other truck and it has the same symptoms. has anyone come across this issue? btw this happened over 2 months ago in mine and a month ago in the other truck, both have been running fine since but id like to figure this out and get these lights off. thank you!

 

Been seeing a lot of these posts lately.

Your replacement alternator is also probably bad. Your charging voltage should be over 14V, like 14.2 or even a little more.

If you take the alternator back and have it bench tested it will probably pass, because it does make voltage, just not enough.

 

3 bad alternators?

 

Are you sure it’s not the batteries themselves? How old are each batteries? If they’re both still original, it kind if points to them as the most likely cause just because they both have the same issues.

I have a 2011 6.2l; new batteries every three years so far. No issues. Original alternator (and I probably just jinxed myself......)


maybe stick a new battery in one truck and see what happens

 

def not original at just over 300,00 miles, lol. its prob a couple years old at the most. ill prob try that tomorow though just to rule it out.

 

tried a new battery, no change. i did find a thread on here where someone had the same issue, he put in a ford alternator and it fixed the problem. ill prob try 1 more napa alternator first, and have the one i took out bench tested. will update with what happens.

 

Yes, I've gone through as many. One member had 4.

 

i just put in the 3rd one a lil bit ago. and put in a new battery last night. im probably going to try a ford one later today.

 

Just curious - are you doing all of the changes (new alternators and batteries) to just one of the trucks?

if you are, maybe take the alternator out of the truck that you haven’t touched yet and put it in the truck that you’ve bern putting the new alternators in just to see if that does anything (assuming the alternators are swappable, of course)

 

the other truck got 1 alternator. everything else is my truck. just picked up an alternator from ford, about to be putting it in. fingers crossed!

 

put in the ford alternator. all set! no battery light, charging fine. strange.

 

I wasn't kidding about the sudden influx of bad rebuilt alternators that we have been seeing. It's been almost an epidemic over the past 6 months or so.

I even resorted to marking the alternators I was returning to make sure I wasn't getting the same ones back.

I wonder if you can still purchase rebuild kits? I need to research that.

 

ive never seen that many bad like that. im not saying that they were rebuilt poorly but i wonder if its a compatibility issue? either way its done now. i appreciate all the help from everyone. now to fix the other truck, lol.

 

I swear there's something with the REGULATORS the rebuilders are using. The alts are capable of charging but they speak Martian and the truck speaks Ford - IOW the ECM is not seeing the communication it expects and trips the light

 

were the batteries load tested.

a shorted battery will burn out alternator after alternator