I have searched through all the threads and cannot find this addressed. I have troubleshot until I am sick of it and can't figure out my charging problem. I have a 1968 F100. It has a new Painless wiring harness, a new G1 type alternator and the third voltage regulator so far on it. When it is setting without running, the battery show 12.6-12.8 volts. When I start it, the voltage drops to 12.3. I have checked the field voltage from the regulator and there isn't any. I have ran a jumper to the field terminal off the battery and the voltage climbs just like it is supposed to. So I am thinking there should be some kind of input voltage to the regulator to cause it to energize the field. The "B" terminal has the battery voltage as it is supposed to. The "I" terminal isn't showing any voltage at the regulator. But according to my multimeter the wire has continuity. I have continuity from the Ground terminal to the ground terminal to the on the alternator. By everything I see, the alternator should be putting out a charging current, but it isn't. Should I run a jumper from the hot side of the coil to the "I" terminal on the regulator to see if that is the problem? I see by some paperwork I have that it is supposed to have around 8 volts on it.

 

I do believe that is the issue, no power to the "I" lug on the regulator.
IIRC with a charge light power comes from the key when in run thru a light bulb, no LED, then to the regulator lug.

You can check this using the factory book on how it is wired.
Can also Google how to wire a regulator & ALT.

Nothing should go on the coil other than power to the + and to the dist. on the - side.
Dave ----

 

OK. I went out to the shop and jumpered a wire to the "I" terminal on the regulator. The Alternator started charging as it is supposed to. Now all I need to do is follow the green/red wire back under the dashboard and find out why it isn't getting and power when the ignition switch is on. BTW, when the truck was first started, the ammeter went well above the neutral line. But as the alternator charged the battery, it fell back to the neutral line. AS advertised. and the battery voltage was showing 13.8 instead of 12.2 as it was before. So contrary to what some have said, the "I" terminal does have to be powered. At least on my truck anyway. (I have seen where some have said that if you have an ammeter, the "I" terminal is not used).

 

Finally got it permanently done. Here is the wiring layout.
B terminal to battery side of the starter solenoid. This senses battery voltage and causes the regulator to turn the charging circuit of the alternator on and off as needed.
F terminal to field terminal on alternator. This energizes the field windings in order for the alternator to produce power.
S terminal to stator on alternator. This assists the main rotor in producing a preset voltage. (In my case 13.8 to 14 volts)
I terminal basically turns the regulator on and off. The required voltage is 4-8 volts. It needs to be connected to the output side of the resistor wire or ballast resistor, depending on which one you have if you have an ammeter instead of a light. The output side of the ballast resistor on my truck is putting out 6 volts.
Ground wire from the regulator case to the alternator case.
If anyone else is dealing with these issues, I hope this helps.

 

On these older points ignition vehicles, there is a bypass wire that comes from the starter lug on the solenoid to the coil to provide 12 volts to the coil for starting. Then when you release the key and the switch drops back to the ignition setting, the power then routes through the resistor wire or ballast resistor to provide 6 volts in order to not burn up the points. So yes there is another circuit to the + side of the coil.

 

On these older points ignition vehicles, there is a bypass wire that comes from the starter lug on the solenoid to the coil to provide 12 volts to the coil for starting. Then when you release the key and the switch drops back to the ignition setting, the power then routes through the resistor wire or ballast resistor to provide 6 volts in order to not burn up the points. So yes there is another circuit to the + side of the coil.

 

Yes that I know but we were not taking dist. points we were taking the "I" lug on the regulator NOT the solenoid.
Re-read my post and you will see this.

What I did not know was if you had a charge light or amp / volt gauge.
I know if you have alight and the bulb is burnt out you have no charging. Was not sure how the gauge did the power to the regulator?
But in the end you got it working
Dave ----

 

Recently had my '67 bumper to bumper Pro re-wired (new custom harness).
I had similar problems with voltages and battery drained overnight.
With the key off, I could detect an ever so slight pulse in the charge gauge.

The electrician trouble shot it and traced it to the ""Instrument panel voltage regulator"".
Did you know there were 2 voltage regulators??
This one is behind the panel and nearest to charge gauge.
I got one at NAPA.
Turns out it's a Ford thing.