Ever since I got my 1972 Ford L8000 it's never charged the battery properly.

The wiring is a hacked up mess... I replaced the alternator with a new one, but that wasn't the problem, as it's still not charging.

Here is a picture of the backside of the Motorcraft alternator:


B is for battery, G is for ground and W is a white wire I took off, not sure what that is for. Those were the only 3 wires hooked up.

I guess I have to rewire this thing myself.

What should the circuit look like? I know the 3208 doesn't need the alternator to run, but right now anything that does need juice is draining the battery, and not utilizing the alternator.

If I check the alternator on any of my vehicles with a multimeter I get 14 volts, I can only get 12.26 at most out of the new & old Motorcraft alternators I have.

Can anyone help me rewire this thing?

Maybe if you know a local guy that,s experienced in wiring of alternators you could have him take a look at it.Sometimes being there is the best way to solve a problem and not guessing from not there to diagnose where it is.

I don't think that Motocraft has an internal regulator, there may be an external regulator someplace on the truck.

It has been my experience when dealing with no charge issues with Ford trucks that when replacing either an alternator or regulator to cure your charging problems you need to replace both at the same time or the bad regulator will take out the alternators as fast as you can replace them.
A bad alternator seems to take out the regulators when they go.
I replace them both every time now.Ron G

scan for 72 ford passenger car -appears to be same as motors truck & diesel- I would say you are missing a wire and have ground in wrong place, but i am tired and having trouble following this
I am having trouble with the scan -send me your Email

There should be a field wire connected to the FLD terminal from the regulator. Should be able to trace it through the harness from the regulator plug. Probably has fried the regulator if it was connected to ground instead of the field terminal.

That alternator is NOT internally regulated. Ford did/does use them in newer vehicles.

I found this on the net:



I'll buy a new regulator & make a new wiring harness, as mine is shot.

One thing I noticed on the 3208, off the alt there is a wire going to what looks like a solenoid on top of the injector pump. I assume this ties into the BAT terminal on the alt?

Also, where would I put the fusible link?

That solenoid is the shutoff (shutdown) for the fuel system so the power should come from the ignition switch in the cab I believe if I remember right.

Yours is better than mine

I got the alternator working just fine.

I bought a new voltage regulator, and a bunch of 10AWG wire, and rewired the whole circuit.

It was totally screwed up from the time I bought the truck, the circut was just wired up totally wrong...