HI, for a few months now I've had the annoying " Check Charging System " light on my 2006 F150 Kingranch and on my 2006 Lincoln Navigator (yes both the same year and the same problem). Well I searched online like crazy, and came up with a lot of threads and complaints about this exact problem. Almost all of the threads ended without any results or fixes. Some of them were wire rubbing issues ( rubbing on a A/C line was one of them that I can remember). I have solved this problem on both trucks. So i figured I'd come online and post what was wrong with my vehicles. Hopefully this helps someone out here that has this problem.

The KingRanch F150 was the first one to have the problem. The "check charging system" light kept coming on and turning off several times during each drive with the vehicle. Checked both the battery and alternator and they checked out GOOD. I put this vehicle on the back burner and figured I'd get to it when I get to it.

Then my 2006 Lincoln Navigator "check charging system light" came on one afternoon. I can't say I was to excited about it, haha. Well this one was different the light stayed on! The next day I started it up and drove to work. When I was done work for the day and got back in to the car and started it started fine. The light was still on... I pulled it forward to line up to my ramps for an oil change and all sorts of lights start coming on (ABS, Advance trace. ext) I think it even started to run rough. I shut it off and tried to restart it, and the battery was dead.

You guessed it... Alternator was shot.

So I go down to Advance Auto and pick up a remanufactured Alternator and installed it while charging the battery. Everything seemed good that night. But the next day the "Check charging system" light came on, was on for a few seconds, then went out. Well this went on for the next few days. Exactly the same symptoms as my 2006 F150! I started checking wires and going crazy trying to figure out why this started to happen right after my alternator went bad!!!!!

I should have thought about it a little harder and went in the direction of the new/ remanufactured alternator in the beginning. I finally realized the intermittent "check charging system" problem was different than when the light came on when the alternator was bad. The light was doing what it was suppose to when the old alternator went bad. But now it is a different problem.....and most likely has to do with the only thing I changed....The alternator!

I brought the alternator back to Advance and returned it for a New alternator (not remanufacture) this time. It was only $30ish dollars more anyway.

I Installed it and sure enough, problem was solved. No more intermittent "check charging system" light.

I repeated this process on the 2006 F150 and it was the same result. Fixed!

I believe the problem is the regulator inside the alternator, I would be willing to bet the remanufactured alternators don't always get new regulators, they might check out good for charging but may have other problems. I say this because the regulator in my "New/Remanufactured" alternator looked old as hell.

Moral of the story, if the light says check charging system and the battery and alternator check out good. You should still assume it could be an internal problem with the alternator. And buy NEW not remanufactured, because its obvious through my searching that ford has an issue with there regulators. So if remanufactures of alternator are re-installing the old regulators in their alternators, this could be what confuses people. Just because it is charging doesn't mean its good. I read a lot of peoples post saying they replaced the alternator and it was still doing the "check charging system" problem.

I know this is a long drawn out post, but If it helps one person then i did good. Thanks for reading!

 

Good job reporting what you've discovered.

 

Robber80, thanks for the post. It looks like I'm almost in the exact same boat as you were, with the exception that my '06 FX4 has not had this problem yet! Wife's '06 Expedition though has been giving me fits. I'd found your post a couple of weeks back, but was hoping that I wasn't going to have to replace the alternator again. Your post/symptoms are exactly the same as mine with the Advance Trac & all sorts of messages/lights including the charging system check when it started. Turned out the alternator was bad, outputting only 10V & it trashed the battery. Alternator had been replaced less than 2 years prior with a re-manufactured from O'reilly Auto. They warranty replaced it and I just had to buy a new battery. Then, 3 days later, the 'Check Charging System' message started back up. From this point to present, I only get the 'charging system' messages, none of the other random stuff. I did find that the Alternator wiring harness (which WAS routed right across the low side AC line) did have some wear on the mesh protector. The marks on the AC line semi-appeared like it could have been some arcing, so I replaced the wiring assembly. No luck, same issues. Checked and re-checked all connections. Re-seated computer connections, pulled the alternator and battery and had checked at Oreilly, which checks good. Re-installed then re-checked again with load. With my meter, shows charging at 14.2V, but will intermittently/randomly drop to as low as 13.2, both with and Without the AC running. Battery is good. Oreilly Auto won't warranty out the alternator because it "checks good" according to them.

Didn't want to, but I guess I'm going to have to just drop the cash and buy a new one. Can't think of anything else....

 

Was wondering if you've had any issues since installing the new alternators? I'm going to the dealership for a new one today.

Thanks,
Steve

 

Well, I went ahead and bought the Ford alternator after speaking with a service advisor. Although they only have re manufactured & don't have 'new' ones anymore. The advisor said that even they have been through up to 3 "new" re-man box opens on a single repair, before they got one that worked right which wouldn't trigger the check charging system message.

I'll post results after I get it replaced today.

 

So, I drove down to Galveston & replaced her alternator again during my lunch. She drove it around some there, home from work, and a little running around here by the house. 50 miles or so & I'm happy to say that the check charging system message has not returned. It may be a little premature to say its 100% fixed, but it was coming on pretty regularly before I put the 2nd alternator on.

Hope this helps someone.

 

Thank you Robber80 for this post.
I have 2009 F150 with the same problem and am wondering if the problem wouldn't also be resolved by tearing down the alternator and replacing the regulator instead of putting on a new alternator. I live in Belize and finding new alternators here can be very pricy.

 

I had the similar kind of problem earlier , I came back from different city almost drive 300 miles away from town . next day I started the car I got this message . I remeber one thing it was lot of humid and sand outside , I parked the car there almost next to the beach . later for a test I had took either carbonator cleaner or wd 40 didn't remember correctly and I had sprayed it all.over the alternator and connection and some how I get out of this problme.
Now almost year back I went to the same place and I came back the problem occurs again , I had tried whatever I did before but no luck.
Only thing it's important if u clean with carbonator cleaner make sure you won't start the car at 12 hrs because it's highly flamable.
I think it's totally related to this stupid.alternator.and because.of.humanity and.sand it making an oxidizing reaction inside which causes this all.stupidity.
Regard s
Umair

 

I had similar problem and did the same as you did. I found a bad ground cable that goes from neg battery post to firewall just bellow ECM. Just cleaned up eyelet and stud and has been working good ever since. Might be a fluke but it worked for my 05 Expedition with the Smart Charging System on the 05 & 06.