So would a problem that would fry the regulator most likely be coming from the S or the A terminal?
I just followed and wrote down EVERY connection to the A terminal. I also made a diagram that's in my gallery:
https://www.ford-trucks.com/user_gal...150246&width=0

 

The only way to fry the regulator like it is, would be to connect a large load to the 'I' terminal. That could be a momentary short from the 'I' terminal to ground.

Is it possible that the regulator was bad from the Auto Store? Maybe someone else fried it and returned it. The Auto Store just put it back into stock.

 

Don't know. The next replacement will be regulator #4. So I'm really doubting they're all bad... I think the first couple fried from the F wire grounding on the body of the alternator, but this one's had nothing like that happen to it.
I'll take it in and trade it out tomorrow and see what happens. I'd do it tonight, but I'm exhausted and just cracked a cold one...
Thanks for all the help danlee & grego!

 

If someone had a vehicle with an Idiot Light, and had a the wire from the 'I' terminal shorted to ground for even one second with the battery connected, they could damage the regulator like this one is damaged. They may have returned the regulator and not have told them what they had done. The store would just put it back into stock, until you got it.

This is why you should disconnect one battery terminal when you fool with the electrical components.

I run a one wire alternator, so I don't normally mess around with a regulator.

 

I wanted to switch to a better alternator, but as my truck was dead in the street two cities away, had to just grab another stock. I miss my old 70 F250. No regulators, just straight hook ups. Hopefully the 'I' shorting out is the problem... We'll see tomorrow. Thanks again!

 

you can check the regulator field relay with your new MM.

Disconnect the regulator from the harness.
Put the MM on Ohm mode, like 1kohm setting or less (not critical)
Connect one probe to the I pin and the other to the A pin.
The MM should show an open connection
If it shows some low number close to or equal to zero then the field contacts are definitely shorted.

If you do the same thing between the I and F pins, (on the 100ohm setting) the MM should show about 10.04 ohms.

Disconnect the battery and measure the ohms between the regulator case and the alternator case. They should both be grounded so you should see close to zero ohms.

 

You have a DuraSpark II ignition right?
If you have an ignition amplifier module and your distributor has the 2 piece cap arrangement (with the wide spacing) then yours is a DSII.

 

While you are checking the regulator (disconnected):

The ohm reading between the I and F pins and the reading between the F pin and the regulator case, would tell us the condition of the limiter relay.

1. If I to F is zero (or very close) and F to case is about 50 then the limiter relay is in the right state.
2. If I to F is around 10ohms and F pin to regulator case is zero then the limiter relay is stuck off.

 

I will be surprised if he gets any resistance readings from the I pin. It looks like the I connection has burned open, but it is worth a try to see if my theory holds water.

 

Try all those resistance measurements at the A terminal. If the contacts are closed, you will get the same readings as the I terminal should.

 

Duraspark II Ignition, yes.

Between the VR body and the Alternator body:
0.5 Ohms (no K in front)

F pin to I pin:
20.5 KOhms

F pin to Case:
20-20.5 KOhms

F pin to A pin:
0.7 Ohms (No K in front)

A pin to case:
7.6 KOhms

A pin to I pin:
31.1 KOhms

I pin to case:
9.29 KOhms

 

The F to A measurement tells us that the field relay is indeed fused shut.
It also tells us that the limiter relay is in it's normal position.

The pin to case measurements are not what I would have expected, given the Ford internal schematic, but some internal damage may be throwing those off.

I have a brand new one of these regulators out in my shop. After I do our weekly shopping trip I will try to repeat the measurements here.

But the bottom line is bad regulator.
Since the A terminal is always live, this explains why the field was always live and the internal damage could account for why the limiter relay didn't open to stop it from over charging.

Ok, so now on to trying to figure out why... next post

 

Next step is to electrically check the harness.
We will do this with the ohm section of your MM, checking for continuity.

Disconnect the battery, the ignition switch, the alternator and the regulator. This way we are only checking the harness. Oh yeah, disconnect the coil and the duraSpark controller. You need to disconnect the battery because if you try to measure resistance (with the MM) on a circuit that already has voltage on it, you will damage the meter (at least pop the internal fuses, if it has them).

1. take a measurement between the A and S pins at the regulator connector. Remember we are measuring the harness, not the regulator. The value should be very high as there should not be continuity until the ignition switch is on.

If you get a low value, then disconnect the ammeter, being careful that the now dangling wires don't touch anything. Then make the same measurement again. If it changes then something is wacked with the ammeter hookup.

Another thing to check is the back side of the Fusebox, something may have melted there and is causing a short. If you can disconnect the wire you labeled as #7, from the fusebox you might be able to determine if it is there.

If the original measurement, at 1., is infinite or very very high, then you need to put some stuff back on the harness and rechecking the measurement, after each addition.
a. the ignition switch
b. DS module
b. the coil.

Did you ever check to make sure the wire from the alternator stator to the choke wasn't grounded?

Maybe Danlee can think of something else. I sure hope we are not just running you around in circles. It is the best we can do without actually being there...

 

It looks like it is wired backwards. The F pin to A pin reads like the A pin to I pin should, and the A pin to I pin reads like the F pin to A pin should.

 

I pulled everything and no matter what, between the A & S on the harness, the meter just said 0.0F. Is this what you mean by an infinite measurement? I triple checked, and none of the wires were grounding on anything.

The MM is working fine, I retested some of the old measurements to make sure.

I pulled the fusebox to check it, and the rear was fine. Wire #7 was connected to a terminal called "Court LPS" which doesn't have a fuse in it.

I did check a while back, and the wire to the choke is fine.

Should I start reconnecting things, and see if the resistance changes?

EDIT: Danlee, just to be sure, I rechecked everything, and those are the correct measurements. So maybe it was wired wrong to begin with?