1974 F100 240ci 2wd. I've replaced the alternator, voltage regulator, battery, battery to engine ground, engine to body ground and all charging wiring and still cant make it charge. Does anybody have any other ideas.

Thanks in advance

 

Tested alternator?

MS

 

Sorry I forgot to add I can jump the alternator straight to the field and it will charge but I've put on 2 new voltage regulators and it still wont charge.

 

did you full-field it at the alternator or the regulator connector? where did you get the new wiring you replace? there is a difference in guage and warning light wiring...

 

I jumped it at the regulator connector and used new 14 gauge auto wire.

 

Does the truck have anything like a Wide Open Throttle switch? It would be on the carb near the throttle linkage, and would be used to cut off the AC compressor when the engine is at full throttle. I'm thinking that these trucks didn't have that (my old 1982 Mustang GT did though) but it's worth checking for. I also had an '84 Capri RS 5.0 which had that switch, and when I threw a different carb without the switch on that car, it wouldn't charge.

 

Nope, no full throttle switch, but thanks for the suggestion. This thing has me stumped.

 

Does it have an ammeter gauge or a charge/battery light? If a light I believe that is what turns on the alternator - be sure it is working/isn't burned out. I could be wrong as all mine have had gauges.

 

If you know the alternator is good, then check your wiring. Follow the wires from the starter relay and you will find a 3 way connection. I had this connection go bad on my F250 and could it would not charge.

 

My 78 wouldn’t charge. Similar steps. Ended up being the connector on the ignition switch. You could squeeze it together and it would charge. Of course, found this after getting new ignition switch. A good zip-tie fixed it. Might be your ignition switch??

 

What they've all said. And check that you re-connected things to the new alternator correctly.
Unfortunately, new parts does not mean they're all good, so any of the new stuff might give you fits tracking the problem because you assume that the new parts are good.

But that's for after nothing else works.
Seems like the Field wire is connected to the alt properly and is in good shape, but the next time you have the regulator connector off test for voltage at the Yellow and Green w/red wires.
The Yellow is hot all the time and should be full battery voltage with no loss.
The Green w/red wire should have 12v only when the key is in ON/RUN.

Not sure just how to test a Ford regulator anymore. Have read the rundown on them before I think, but don't remember the steps. Will look and see if the aftermarket manuals list the troubleshooting steps.
Were the connections on the back of the new alternator the same as the old? The BAT post has the red insulator? The FLD post used to be orange, but newer alternators seem to use either black or white I think? The STA post might be black.
But only the FLD and BAT posts really matter at this point.

I know you said you got the alternator to work when you full-fielded it, but did you just hear it bog the engine down, or did you check the voltage at the battery when you did this?
Not sure it actually matters, but still good to know.

Paul

 

Hey Paul, thanks for the tips. The new alternator has the same locations as the old but to be sure I swapped the field and stator wires and it didnt do anything. I had a voltmeter hooked to the battery so I saw the full-field charging there. My next day off I'm going to start with grounding out the indicator wire right at the regulator to see if that changes anything then I'll probably add a radiator support to frame ground and go from there.

 

Maybe there's a spread-open female terminal in a connector somewhere. I'd first check at the voltage regulator.

And did anyone mention the voltage regulator ground? I think the ground is the attachment bolt/screws, but if the voltage regulator case isn't contacting the rest of the truck for a ground, then I'm pretty sure that the system won't work.

I wondered about the Alternator Warning Lamp bulb, but I'm thinking that a blown/missing bulb won't keep it from charging. But I've heard it will on other makes.

I am more sure that a bad ammeter won't keep it from charging - unless the charge wire is broken at a point past where the ammeter wire connects - which would leave all of that current to be pulled through the gauge, and would probably let the smoke out of the gauge in short order.

Three of some of the most important things about electricity are a tight connection, a tight connection, and a tight connection.

 

Thanks meangreen, Its got a new voltage regulator connector I wired in last week and it felt tight but I'll check again, the other ends are new ring terminals. I direct grounded the voltage regulator to the motor thinking the same thing, that it might not have a solid contact to the rad support, but it still didnt help. I'll find it eventually, dadgum wiring gremlins. Did you go to North Texas or do you have a green truck?

 

Used to have a green Mustang.