Odd voltage regulator issue

[Nacho-RT74]

I don't get the reasoning about eliminate the field wire going throught the bulkhead, because the field wire is spliced on to the RUN circuit which still runs through the bulkhead.

The wire being eliminated from the bulkhead ( hence also from ign switch ) it was the Ballast bypass, being taken from an extra prong on starter relay. It was also added at ign switch an extra ACC source wire for several accesories into the cab

 

[383man]

I don't get the reasoning about eliminate the field wire going throught the bulkhead, because the field wire is spliced on to the RUN circuit which still runs through the bulkhead.

The wire being eliminated from the bulkhead ( hence also from ign switch ) it was the Ballast bypass, being taken from an extra prong on starter relay. It was also added at ign switch an extra ACC source wire for several accesories into the cab

Yes the field wire is from the J2 circuit which is why all of that is eliminated with the field loads relay. The winding is controlled by the J2 circuit so all the current to the field comes right from the battery to feed the field and for the battery sense circuit on the volt regulator. Gives a true
battery volts sense and no voltage drop from the wiring through the bulkhead and ign switch. Its not the ballast bypass I am talking about as the field loads relay has nothing to do with that. That was when they added the extra terminal to the starter relay to bypass the ballast when cranking. The fields load relay is completly seperate from that and has nothing to do with the ballast bypass. It is basically just putting a relay in to power the field and battery sense right from the battery. Course it is a fused circuit. They did not use it much which I dont know why as it was a good idea. Hardly ever saw it on a car in the field but saw it in a few Motor manuals and Chrysler training. Ron

 

[RJRENTON]

Yes the field wire is from the J2 circuit which is why all of that is eliminated with the field loads relay. The winding is controlled by the J2 circuit so all the current to the field comes right from the battery to feed the field and for the battery sense circuit on the volt regulator. Gives a true
battery volts sense and no voltage drop from the wiring through the bulkhead and ign switch. Its not the ballast bypass I am talking about as the field loads relay has nothing to do with that. That was when they added the extra terminal to the starter relay to bypass the ballast when cranking. The fields load relay is completly seperate from that and has nothing to do with the ballast bypass. It is basically just putting a relay in to power the field and battery sense right from the battery. Course it is a fused circuit. They did not use it much which I dont know why as it was a good idea. Hardly ever saw it on a car in the field but saw it in a few Motor manuals and Chrysler training. Ron

EXCELLENT EXPLANATION and the reason for the circuit. Supplying battery voltage to the regulator as a reference rather than thru the afore mentioned "explanation" (#21), says it all !!
BOB RENTON

 

[hunt2elk]

Time to update this thread. Rechecked all my connections, added another ground wire to the voltage regulator, tried 3 different MP regulators. Things seemed to be better but every once in awhile the voltage would creep above 15 again. Would stay there until the next time I drove the car, and then be normal again. Decided to find a new ignition switch as that is the only 51 year old original part on the car. Thanks to Ray @HALIFAXHOPS I got an original BW from the 70's. Swapped that in today and so far everything is perfect. I have a feeling the original switch was causing all the problems.
On another note. I talked to Mark at MAD Electrical today and he is really promoting adding a relay in the voltage regulator sensing circuit, I believe just like 383man posted about above. He is sending me a drawing and I will post it here when it shows up.

 

[72RoadrunnerGTX]

 

[hunt2elk]

One good thing to do to our older Mopars is put a relay in to power the voltage regulator battery sense circuit. Later Mopar did this on some cars and called it a field loads relay. Basically to take the 12 volt key run wire to the reg and run that to a relay coil and then ground the relay coil. It will only power when the key is in the run mode. Then wire the relay right from the battery to the voltage reg volts sense circuit. It works great because you eliminate the ign switch and any bad connection between the ign switch and reg. You get battery volts right to the reg. It will let the reg see a much more accurate battery volts.
As for the volts changing yes all factory voltage regulators sense ambient temps as it raises the set voltage in colder weather. But that said when its 80 degrees out it may charge at 13.6 and when its 20 degrees it may be at 15. But I have never seen any change a full volt from underhood temps as eng warms up. Yes they sense ambient outside temps and adjust the voltage setting accordingly. But as I said I have not seen any change much if any just by the eng underhood temps. In the summer my volts is around 14.2 and it stays at 14.2 from a cold eng to 190 degrees in the eng. I may be wrong but I believe they only sense the volts at key on and keep that setting until the next start. Good luck with it. Ron

Here are a couple of sheets I just received from Mark at MAD. I think this is what you are referring to by adding a relay in the voltage regulator circuit?