Yesterday, I had my small utility trailer on the hitch of my 2003 F-250. I had dropped the trailer off and then put it back on the ball. Since it was near nightfall, I checked for running lights on the trailer. No luck. I messed with the 4X connector for a bit and finally gave up, choosing to leave the trailer until daylight. On the way home, the battery indicator and ABS indicator lit up on the dash display. I stopped the truck to inspect and barely got it restarted. I made it another two miles and the truck would not run. This morning, I went back to truck with a fully charged battery, installed it, and made the 5 mile drive to home. All indicator lamps are now off but measuring across battery posts with engine running, I'm seeing 12.3V. All symptoms point toward a failed alternator but this charging system has been flawless for 11 years. Is it possible that I blew a fusible link or some other circuit interruption instead of a failed alternator?Anyone have any diagnostic tips for me?

Oh it has to wear out sometime. It chose THEN. Nothing wrong with what you did. Reminds me of my mother years ago when she picked up the phone to make a call. The phone chose to ring and the receiver hit the ceiling. Boy was she mad!If you wish to check all the underhood fuses before replacing the relic. The 6G is not cheap. See how much your Ford dealer wants for a reman.

West, On an 14yo truck, anything is possible. You don't give a hint where you are, but there are lots of simple things that could be the problem. Get a meter, get the truck charged enough to start and watch the battery voltage. If it goes up, maybe the alternator is not your problem. Once it is running, put the meter on the stud on the alternator. If it is making power, that is not your problem. If it isn't, it is time for a rebuilt. Good Luck Matt

Thanks for the replies. With engine running, measurement from alternator stud (red terminal insulator) to ground is .245V.I so want this to be a bad fusible link or relay instead of failed alternator. The coincident trailer light manipulations where I left the headlights on for a few minutes right before the issues with the truck, is either a red herring or is the root. This afternoon, when I have transportation, I'll take the alternator to the local parts distributor and have them test the alternator. Maybe there's some way I can test for continuity across the fusible links in the interim.

Continuity? Naw. Test voltage on both sides.

donn0128 wrote:Continuity? Naw. Test voltage on both sides.Same,same.Just so happens my Fluke clamp meter isn't working so will have to do some surgery to get some measurements across the links. I'll try for the least invasive method. Nearly all the wires in the engine compartment are loomed from connector to connector.

Ford Superduty battery and charging issue | Good Sam Community

36 Replies

MEXICOWANDERER
Explorer
Aug 31, 2015
Naw my wrist snapped when a rattan chair broke in 2011 down here. Back in the eighties eaely nineties I was a wild - man working 15-17 hours a day. Then scooting for Mexico after Xmas. I would shower and ten seconds after my head hit the pillow ZZZZZZZ. Fun days. I shouldn't complain
westend
Explorer
Aug 31, 2015
Amazing, Mex!
Good to hear that there are still some on the Planet that have knowledge and can put it to use. I'm also thinking you may have the record for single-handed rebuilds.
MEXICOWANDERER
Explorer
Aug 30, 2015
It's nice to know I am not totally obsolete and useless. Spent too many danged hours on that bench sitting in a swivel seat with high backrest. I had four butterfly air guns dangling by coil hoses custom setuo for a particular alternator group. Swivel 180 degrees and there was the test bench. I had a digital dash out of a Crown Vic. Ready to test the white regulator 3-G models. Transformer carbon pinzer soldering aid with needle air for desoldering. Bare bearing roller shaft for rotor balancing and I turned slip rings to half-a-thousandths LS rotabrator and hot water washing machines an LS rebuilder's 10 HP rebuilder's press. A truly vertical learning curve. Would I do it all over again? Some ten or fifteen thousand alternarors? Oh hell yes. My record is (43) CS-130 alts in one day. I had a helper to carry bins to the washer and rotabrator.
westend
Explorer
Aug 30, 2015
MEXICOWANDERER wrote:
For westend

Just as I thought the original is a 3-G and the replacement is a 4-G

Idiot! Parts counter personnel. That 3G is a 130 amp model. I would not patronize that business again.
Nor I.
I ended this fiasco by returning the Motorcraft alternator, the new connector, the new (incorrect) pulley, and visited another store that had the exact replacement alternator. All installed and pushing 14.35V after start up.

Mex, thanks for your help on this. I learned a few things about alternators and learning new things is always a plus. This also gave me a moment to clean up my battery tray, polish up the connectors, and check electrolyte--along with a charge and equalization session. Hopefully, good for a few thousand more miles.
MEXICOWANDERER
Explorer
Aug 30, 2015
For westend

Just as I thought the original is a 3-G and the replacement is a 4-G

Idiot! Parts counter personnel. That 3G is a 130 amp model. I would not patronize that business again.
MEXICOWANDERER
Explorer
Aug 30, 2015
To senor RJ
For a fast fixit there is nothing wrong with your suggestion. Have you got a T10 Torx male socket to remove the brush holder reg assembly? Parts store prices are stupidly expensive for bearings and brushes.

You find a bit of brush left. Time to reassemble the alt?

Alternators using a 2000XX rear ball bearing love to eat out the slip ring end bearing bore. Delco went to far as to incorporate a one-time-use tolerance ring to compensate. For durability and reliability it is one tough job to beat a new or reman factory alternator.

For fun call your parts store and ask them the price of a set of bearings for oh say a 1992 Ford pickup with V8.
MEXICOWANDERER
Explorer
Aug 30, 2015
Exactly correct senor Westend. If you get battery but no test light in either of the remaining connectors check for a glowing ALT light on the dash. A glowing when probed ALT light means that alternator volt reg connector is seeing good signal to fire off the reg. Volt reg should climb to 14.4 then sag as reg temps climb unless you have a really hot day.
westend
Explorer
Aug 30, 2015
RJsfishin wrote:
I'd still wonder why not a set of brushes and a bearing in the old one ?

Ok, I must have missed something.
Because there are other issues besides or not including the bearing and brushes.

Pictures as requested.

The original alternator and picture of the three pin connector:

New alternator and new connector:

Edit--Picture of new three pin connector and pigtail (my ink on the connector):

westend wrote:
If one terminal is to battery voltage reference and the battery is installed and connected, I should have 12V on that wire, correct? Would I also have 12V on the other wire when the key is turned on?

Connected battery and this is exactly the situation with the old connector---one wire having constant 12v and the other with voltage present only when the key is turned. I'm going to start soldering the new connector pigtail onto the original wiring. If I get it wrong, hopefully someone can correct me.
RJsfishin
Explorer
Aug 30, 2015
I'd still wonder why not a set of brushes and a bearing in the old one ?

Ok, I must have missed something.
westend
Explorer
Aug 30, 2015
Thanks Mex, this now seems resolvable. No digital dashboards in this F-250. No alternator warning light, either. I can get some pictures up later today.

If one terminal is to battery voltage reference and the battery is installed and connected, I should have 12V on that wire, correct? Would I also have 12V on the other wire when the key is turned on?