Hi, I have a 2003 F350 6.0. I had a flickering Battery lt on the dash last week so I replaced the Alternator. People recommended I upgrade to the 2005 140 amp alt from my stock 110. I have a single alt system. So I did, today it died on way to work. Batteries were drained. Had new alt checked and its fine. So All I have is a wiring diagram from 99-2002 but it shows the plug on the alt with 2 wires, Lt grn/red from switched ign and Org/Lt Blu which goes to batteries. Org/Lt blu has 12v but Lt green/Red has nothing with ign sw on. I did check fuse 45 in Central J box and have power there. I did notice I have no battery Lt on dash when you turn Ign sw on, and never got the Lt this morning when it died. What Im confused about is do I have a PCM? my diagrams that only go up to 2002 model show it for a 2 alt sys but not for a single alt. I should have power on Lt Grn/red with ign sw on correct? Everyone said 2005 alt was plug and play, the elec connector is now pointed down, where it was pointed up on the orig alt, look to be wired the same. Any help will be greatly appreciated.

Dave

 

Once you charge the batteries back up....start it and check voltage at batteries and at alternator on big wire. 13+ volts means good alternator. (and wiring)

 

Had alt tested at auto parts place and they say its good, but in the truck I have no volts at big wire post on alt when running (with big battery wire disconnected) Otherwise you would just be reading the battery right? Should have power to both small wires at alt with ign sw on right?

 

Sometimes the parts guys show two alternators in the dual system... you needed the upper one. Hopefully someone that can help will be along shortly.

 

Found it! The small Lt Grn/Red wire was broken right at the connector for the Alt. What made it interesting was it was broken inside the insulation and looked connected. I wiggled it the right way and got the voltage with ignition sw on, so I gave it a tug and sure as S**T it broke right behind the pin in the connector. So off to FORD for repair connector. $50.15 for a 14S411 connector. Thats crazy! but what you gona do. Glad I found it. Maybe that will help someone someday.

Dave

 

Glad when folks report back what they found. I have noticed many a thread where someone created an account just to seek help, only to disappear for good, or never tell us what the diagnosis and repair was.
I realize it takes time and effort to post what the end result was, and glad to know what you found. The odds are that someone along the line will have something like this happen, or if nothing else will make someone take a closer look at the wiring.

 

I had a very similar problem today. Alternator wasn't charging and had a lifetime warranty so I yanked it off and swapped it for another one at Autozone. Bought one there in the first place so if I had a problem on the road it would be an easy exchange, but I digress.

Put the new alternator on and the dang thing wouldn't charge. I checked everything that was obvious (wires, fuses, ect) but found nothing. Checked my Scangauge and no fault codes. Took it to a friend that was a former Ford tech and had done work for me in the past. He went over it and couldn't find anything wrong (including the Alt connector).

After about an hour of testing fuses and connections he remembered something he had seen before. There is a wiring harness connector between the fender and right hand battery that goes to the 2nd alternator if you have one. If you don't have one it's just a loop or jumper connection. A mouse had chewed through the jumper wire. He said for some reason mice love that wire. A 10 cent crimp butt connector and everything started working.

Thought I better post this on here for the next unfortunate victim.

 

Knowledge is power, and the more folks that post something that happened the better of we all are in the long run!
It might be a case of something happening with my/your truck that only two more guys have happen to theirs, but it will save those two a lot of head scratching.