Charging Mystery - 69 GTX

[ToddMcF2002]

Hi folks 69 GTX here with 70 style voltage regulator. I just replaced the regulator because it refused to send any signal to the field wire (green). The blue wire is definitely getting power. The case is definitely grounded. If I jump the field wire the alternator charges, ammeter shows it charging.

1st pic: Here is the regulator with the jump wire to field - its the only way I can get the alternator working

2nd pic: The single field alternator

3rd pic: The case ground. Its definitely grounded

 

[Rockland71GTX]

You can't use the later style regulator with a single field alternator. The green field wire varies the ground side of the field, your alternator has the field grounded by the case. Get a later style alternator or earlier style regulator, you can't mix the 2.

 

[ToddMcF2002]

You can't use the later style regulator with a single field alternator. The green field wire varies the ground side of the field, your alternator has the field grounded by the case. Get a later style alternator or earlier style regulator, you can't mix the 2.

You know I figured it was something like that. I didn't build this car so I'm not surprised. Any chance you can recommend a regulator? I know the alternator is working. And thank you!

 

[70chall440]

There are a lot of regulators out there and I suspect many are made in the same place so its a bit of a crap shoot regardless of the brand. That said, I'd probably recommend a NAPA product if buying local. You can test the regulator if you have a variable power source and a test light, there is a video on you tube on it.

 

[ToddMcF2002]

There are a lot of regulators out there and I suspect many are made in the same place so its a bit of a crap shoot regardless of the brand. That said, I'd probably recommend a NAPA product if buying local. You can test the regulator if you have a variable power source and a test light, there is a video on you tube on it.

Yup I ordered a nice DC variable power supply last night I'm tired of stealing car batteries to test stuff and I need to vary the voltage for this test. So just order a regulator from NAPA meant for a 68 or 69?

 

[70chall440]

Yup I ordered a nice DC variable power supply last night I'm tired of stealing car batteries to test stuff and I need to vary the voltage for this test. So just order a regulator from NAPA meant for a 68 or 69?

Well if you have a 70 up style regulator I suspect you would need that one. They are all pretty much the same as far as I know. There is a variable one out there in the aftermarket but am not sure how well it works.

 

[70chall440]

https://store.alternatorparts.com/partnoc8313.aspx

 

[ToddMcF2002]

I've already tried (2) 70 style regulators. My alternator expects a 12V signal on the field wire to run (that's my understanding) and neither of the 70 style regulators are showing voltage on the field output.

 

[Rockland71GTX]

https://store.alternatorparts.com/partnoc8313.aspx

That's the type he has which won't work. He needs the earlier type. I checked rockauto and they show Standard Motor Products VR101 but it is not in stock, you may find it elsewhere. Check through the wiring harness to make sure the previous owner didn't screw anything else up!!! Get a manual here: Service Manuals – MyMopar

 

[R413]

Run that ground wire to the engine. There is an open bolt hole at the top rear of the right side head. Near the intake bolt. The factory had one there and you need it also.

Right now the firewall connected to the firewall with a wire. It’s doing nothing.

 

[Rockland71GTX]

Do you have a blue connector at the alternator? Do a continuity check between it and the regulator. If that is wired correctly it will be easier to change the alternator.

 

[ToddMcF2002]

Run that ground wire to the engine. There is an open bolt hole at the top rear of the right side head. Near the intake bolt. The factory had one there and you need it also.

Right now the firewall connected to the firewall with a wire. It’s doing nothing.

The ground strap you see there goes to the bolt you are talking about.

 

[ToddMcF2002]

That's the type he has which won't work. He needs the earlier type. I checked rockauto and they show Standard Motor Products VR101 but it is not in stock, you may find it elsewhere. Check through the wiring harness to make sure the previous owner didn't screw anything else up!!! Get a manual here: Service Manuals – MyMopar

I think you are right on the VR101 - I'll try to locate one. But just to be super clear the box is definitely grounded and the blue wire is getting 12V clean. If I jump the terminals she charges. So the idea of a mismatched regulator / alternator combo just makes sense. I'm no electrical expert and I had no idea they changed the way the regulators worked after 69 - apparently neither did the previous owner who told me he "just changed the alternator". Clearly he was struggling and being a classic "seller" passed his problem to me.

 

[Rockland71GTX]

It seems that he got the wrong alternator. Check to see if you have both the blue and green wires and if so check continuity to the plug for the regulator. It may be correctly wired for the later style alternator.
The earlier style alternator had one side of the field in the alternator grounded to the case. The regulator for that only had one field wire going to the alt. that varied the voltage to control the output.
The later style alt. had 2 field wires connected to the regulator. The blue wire supplied the positive voltage, and the green wire varied the ground in order to regulate output.

 

[Darter6]

AutoZone Duralast VR 706 is the electronic replacement for 69 and older Mopars.
Also known as Wells VR 706

 

[ToddMcF2002]

It seems that he got the wrong alternator. Check to see if you have both the blue and green wires and if so check continuity to the plug for the regulator. It may be correctly wired for the later style alternator.
The earlier style alternator had one side of the field in the alternator grounded to the case. The regulator for that only had one field wire going to the alt. that varied the voltage to control the output.
The later style alt. had 2 field wires connected to the regulator. The blue wire supplied the positive voltage, and the green wire varied the ground in order to regulate output.

The 70 regulator only has (2) pins even though its a 3 pin connector. One has to be voltage and one field. Isn't the second field wire on those compatible alternators just grounding to the alternator case? Otherwise your answer is real clear and thank you for that.

 

[ToddMcF2002]

AutoZone Duralast VR 706 is the electronic replacement for 69 and older Mopars.
Also known as Wells VR 706

Thanks for that I just ordered one from NAPA and it looks the same as that AutoZone one

 

[RJRENTON]

It seems that he got the wrong alternator. Check to see if you have both the blue and green wires and if so check continuity to the plug for the regulator. It may be correctly wired for the later style alternator.
The earlier style alternator had one side of the field in the alternator grounded to the case. The regulator for that only had one field wire going to the alt. that varied the voltage to control the output.
The later style alt. had 2 field wires connected to the regulator. The blue wire supplied the positive voltage, and the green wire varied the ground in order to regulate output.

Partially correct.....the current flow is thru the BLUE wire TO the alternator. The GREEN wire runs FROM the alternator to the regulator which, thru an internal transistor to ground, which completes the field current circuit. The BLUE wire at the REGULATOR provides the reference voltage to the regulator for the control point (~14.5 volts at the battery). The alternator's output is controlled by varying the rotating field's current thru the regulator to ground. A verified ground at the regulator is required. Both alternator brush holders MUST be isolated from the alternator's case or frame.
BOB RENTON

 

[Don Frelier]

Run that ground wire to the engine. There is an open bolt hole at the top rear of the right side head. Near the intake bolt. The factory had one there and you need it also.

Right now the firewall connected to the firewall with a wire. It’s doing nothing.

I see a heavy braided ground cable from the firewall that bolts to the engine.
Looks ok the way it is to me.

 

[ToddMcF2002]

Here is the one I've ordered. I'm assuming I'll see some kind of voltage on the FLD terminal when voltage on IGN is less than ~14.5 volts