Voltage Regulator problem

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Angryman

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Sorry for long post. 73 Duster originally a /6 but swapped to 318 and 904 before I got it. Went to start it the other day and battery was dead. Put it on the charger and got it started. Put my digital voltmeter on it on got 12.6. Drove it around a bit then stopped at the parts store to have them test the battery and alt thinking I had a bad battery. Test said battery and alt were fine but voltage regulator was bad. Looking around I found this.
reg.jpg

Voltage regulator bolted to the firewall but nothing hooked up to it. Thinking I had somehow knocked the plug off at some point in time looked for it to hook it back up. Nothing. Cant find a plug anywhere. This is what the alt looks like.
alt.jpg

Has someone before me converted to 1 wire alt?
 
No. I would take another look for the wires. I can only assume the 1 field wire on alternator is powered by the ignition switch. Other field wire goes to regulator,then 2nd terminal on reg goes to ign to monitor voltage.
 
That alternator appears to be the proper isolated field (incorrectly called "dual field) BUT ONE TERMINAL is not connected. This could NEVER have worked No idea what happened with the regulator---is there a connector?

Basically "ignition run" power from the key hooks to the VR IGN terminal and to one of the alternator field terminals. The second field terminal goes back to the regulator field terminal.

The very basic circuit: VR MUST be grounded. MUST!!

moparpost70.gif
 
I would start at the alternator and follow the 1 field wire back to where it comes from. I am not aware of a 1wire (internal regulator) alt conversion for square back alternators.

As 67dart273 pointed out, not sure how it ever worked as is right now.

Quick test. Disconnect the field wire in photo 2. Measure resistance to ground on both the field terminals and report back
 
I am currently opening up the wire harness and tracing wires. I am "guessing" that the few times I have driven the car this summer have been all on battery power.
 
upload_2021-7-20_17-59-1.png


One should be blue and the other should be green. At the alternator end they should be wrapped into the same harness.

The regulator end will be a molded connector plug to mate with the triangular reciever.
upload_2021-7-20_18-13-18.png
 
Okay I got the harness all unwrapped. There are only 2 wires coming out of the alt. 1 larger gauge wire which I assume is the charge wire? It goes into the bulkhead connector.
The other smaller wire goes into this junction which has been laying on the intake manifold since I got the car
4.jpg

then it T's before entering the bulkhead.
3.jpg

From the T 1 wire continues onto the ballast resistor
2.jpg

and the other just dead ends at this connector near the battery
1.jpg
 
View attachment 1715768638

One should be blue and the other should be green. At the alternator end they should be wrapped into the same harness.

The regulator end will be a molded connector plug to mate with the triangular reciever.
View attachment 1715768649

This is that wire. They are both blue.
5.jpg


There is no molded connector for the V/R anywhere on the car I can find. Had a friend over helping me look and he could not find 1 either.
 
Looks like you have 2 wires twisted together, what are they for?

The wire that is twisted together I only just found while looking for the V/R plug. I will be repairing it. It goes here to the starter relay.
6.jpg
 
Alternator should have a blue and a green wire
Voltage Regulator should have a blue and a green wire
The green wire only exist between the Alternator and Voltage Regulator no other connections
The blue wire goes to the coil and ballast resistor and bulkhead along with the Alternator and Voltage Regulator, all connect in one way or another.


Alan
 
I'm not sure that wire belongs on the starter relay, unplug in from the relay, turn key on and see if it (the wire) has voltage?


Alan
 
This is that wire. They are both blue.
Is the main harness still wrapped?

As far as what you are holding . The blue ignition wire was used to power several items.
1. ignition itself (power to coil and ecu if so equiped)
2. Power to alternator rotor
3. Tells Voltage regulator what the system voltage is.
Then often a few other items were added. We can look at the 73 FSM to see what else and how it was connected.
 
That wire from the starter relay should lead down the firewall and to the neutral safety switch on the transmission. The connector for the VR should be right there somewhere otherwise someone chopped it off. "It appears" that the two twisted together may well be the VR wires. Blue should be switched 12V to the VR and green goes to the disconnected field on the alternator. See if you can find the other end of the green if that is what that is, there, "twisted".

There is only one so called "run" wire coming from the key, through the bulkhead, into the engine bay. BE CAREFUL it is NOT FUSED. That wire splits off to feed loads under the hood, the ignition system, the VR, one alternator field, the choke, and any smog equipment "may not be present"
 
By the way you need to get your tail over to mymopar and download the two volumes of '73 service manual, that is, body, and chassis.
 
Might be worth checking the VIN. Diagram shows a wire for throttle solenoid for 340s that connects there. Not that the shop manul is always 100% accurate, but worth checking.
upload_2021-7-20_18-50-32.png


CE 2(N) is the wire coming out of cavity N in the firewall connector.
It goes to a welded splice that's in the wrap.
From that branches out
one wire to the ignition J2A
a wire to the regulator J2B (that senses voltage)
a wire to a connector, that then joins two braches - one to the choke assist and one to the alternator rotor.

Originally there was a multi-cavity connector near the back of the engine. Check for the the green field in that, if its still there. Probably was on top of or along side the valve cover.
upload_2021-7-20_19-1-14.png
 
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The spliced wire to the starter relay was spliced again just before this connector that leads into the bulkhead. I removed the wire from the starter relay and there was no power to the starter. Hooked it back up and the car turned over.
7.jpg
8.jpg
 
Might be worth checking the VIN. Diagram shows a wire for throttle solenoid for 340s that connects there. Not that the shop manul is always 100% accurate, but worth checking.
View attachment 1715768677

CE 2(N) is the wire coming out of cavity N in the firewall connector.
It goes to a welded splice that's in the wrap.
From that branches out
one wire to the ignition J2A
a wire to the regulator J2B (that senses voltage)
a wire to a connector, that then joins two braches - one to the choke assist and one to the alternator rotor.

Originally there was a multi-cavity connector near the back of the engine. Check for the the green field in that, if its still there. Probably was on top of or along side the valve cover.
View attachment 1715768682

I ran the VIN and it's just a 73 with a /6
 
JUST MY HUMBLE OPIONION...

there is so much wrong with this wiring that I would get a doner car or aftermarket OEM replacement wiring harness for your car.

If your car started life as a /6 and it is now a V8 buy a year correct V8 engine harness.

Lastly please do as I mentioned earlier about measuring the resistance of the two field wires and report back. It is posable that your alternator has one of its field wires internally grounded, so a single wire to the other field would cause the alt to charge.

How it would be regulated.... Maybe the blue wire is going through a resister of sorts, to get the voltage down to 7 to 10 volts effectively regulating the alt to not over charge. Or it has beenhooked to 12v and overcharging all along.
 
just run a wire from the open field to one of the 2 on the regulator. The other blue wire just taps into the other regulator pin on its way from the jumpered side of the dual ballast resisitor.
 
JUST MY HUMBLE OPIONION...

there is so much wrong with this wiring that I would get a doner car or aftermarket OEM replacement wiring harness for your car.

If your car started life as a /6 and it is now a V8 buy a year correct V8 engine harness.

Lastly please do as I mentioned earlier about measuring the resistance of the two field wires and report back. It is posable that your alternator has one of its field wires internally grounded, so a single wire to the other field would cause the alt to charge.

How it would be regulated.... Maybe the blue wire is going through a resister of sorts, to get the voltage down to 7 to 10 volts effectively regulating the alt to not over charge. Or it has beenhooked to 12v and overcharging all along.

My plan is to rewire the whole car. Was just hoping to get this summer and hopefully next before I did. Not sure I did your resistance test correctly or not but I got "OL" results on both.
 
Not sure I did your resistance test correctly or not but I got "OL" results on both.
Perfect, that's what you should get for a Dual wire, floating / isolated field alternator.

Assuming the rest of the harness is usable you can rewire the field / voltage regulator cir.

Just run new wires per the sketch in post 4 from ignition side of ballast resister, to the voltage regulator to one of the field terminals, the other field terminal to the other pin on the voltage regulator per the layout in post 7.

The existing blue wire might be good to go, as pishta pointed out. Then just adding the green wire from field terminal to regulator will do ya.
 
My plan is to rewire the whole car. Was just hoping to get this summer and hopefully next before I did. Not sure I did your resistance test correctly or not but I got "OL" results on both.
That's correct. Touching either terminal while the other probe is touching ground should show no connection.
Touch a probe on each terminal and there should be a connection. They connect through the rotor.
Rotor and slip rings shown here. Identifying Chrysler Alternators (1960-1976)

Can you fix this? Possibly yes. It will take some time and patience.
For materials, some shrink tubing (prob oil resistant would be best in the engine bay) and some means to rejoin wires and likely crimp terminals.

Lets see what you got here
 
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