Re-wiring the truck for an OEM voltage regulator: 3-wire pinout?

[procomsignathid]

I'm hoping some of you might be able to help... My truck (1978) was re-wired to use an aftermarket voltage regulator, and they snipped the plug in the process. I still have the wires with the correct color (only to spade connectors instead of a green plug):

• Black/Yellow: Ignition
• White/Green: Field
• White/Black: Earth/Ground

I am trying to understand the pinout of the new voltage regulator I purchased... The internal wiring isn't adding up for me (I'm probably missing something simple). I really don't want to get this wrong as it could lead to an electrical fire (I'm pretty sure anyways). Anyhow, the new regulator is from CityRacer (OEM equivalent). Here are some pics:

The manual I have (2F Engine Repair Manual) shows the following pinout for the plug:

To me, this would indicate the following:

• Red Wire = Ignition
• White Wire = Field

However, looking through this post by @bj40green and following the wires, I suspect the wiring may be opposite of this. Here's the diagram that's throwing me off (from that thread):

Most notably, P0 (the contact that moves between P1 and P2) is connected directly to the Field wire. Looking at the above pics, the red wire is riveted to the metal structure that holds the contact that moves between points.

Am I getting something off? I figure I would check here before I do something really stupid (I'd rather be embarrassed and have a truck that isnt on fire).

 

[procomsignathid]

Posting again here with some more detail. Could you all confirm my thinking?

1. The red wire, which is connected to rivet #4 (and thus the metal armature that supports the plastic electromagnet spool) is connected to P0, the contact that moves between P1 and P2 depending on the state of the electromagnet
2. The white wire, which is connected to rivets #2 and 3, is connected to one end of the electromagnet winding and P1
3. The blue wire, which is connected to rivet #1 and ground, is connected to the other end of the electromagnet and P2

If y'all agree with those 3 points, based on the Toyota diagram above (figure 8-16), would you all come to the conclusion that the RED wire is the Field wire?

 

[Racer65]

There are two types of alternator plugs. From '77 onwards, it has the "green plug", with F-E-N, where F is at the top. Prior to '77, the configuration was E-F-N, with E at the top. The diagram in the factory manual only shows the earlier configuration, because it was published prior to '77. The voltage regulator you received is specifically for '77-'78, thus it matches the green plug configuration.

 

[Racer65]

 

[procomsignathid]

Thank you for replying @Racer65, but you're showing the alternator side, IIRC the only connection between the alternator and the regulator is the Field (F) wire, with Earth (E) going to ground. Does N refer to Ignition?

Can you confirm my wiring assumptions are correct? (the field wire should be connected to Point-0, which is to say, the contact that moves between Point 1 and Point 2)

 

[DirtDauberGarage]

OK, here are my two cents according to the way my 78 is wired up.

ACCORDING TO YOUR PICK BELOW...

1. What you label as the BLUE wire is GROUND. Mine connects to a WHITE with BLACK stripe wire. The previous owner cut it and made it a dedicated ground. I didn't change it back when I replaced the voltage regulator because it worked fine and seemed like a good idea to ground it right at the regulator.

2. What you label as the RED wire on mine connects to a BLACK wire with a YELLOW strip on it.

3. What you label as the WHITE on mine connects to the white wire with the GREEN stripe

 

[procomsignathid]

@DirtDauberGarage, I agree that's the way the stock wiring should work, but both the wiring schematics from Toyota and the Haynes seem to agree that the Field wire (which would be the white w/ green stripe) connects to the Point-0 armature within the regulator itself. In mine, that would be the red wire that connects to P0. I think the ignition and field wires were swapped in my plug (the white wire should connect to the vehicles black/yellow).

 

[DirtDauberGarage]

OK, I took mine off and took a pic of the bottom side. Here is how mine is wired...

1. RED and WHITE wire on my voltage regulator connects with the BLACK and YELLOW wire on my Toyota Land Cruiser.

2. GREEN and WHITE wire on my voltage regulator connects to the same GREEN and WHITE on TLC

3. BLACK and WHITE wire on my voltage regulator goes to the same BLACK and WHITE wire my TLC.


Let me know if you need me to take the cover off and take a pic or the inside of the voltage regulator.

 

[DirtDauberGarage]

From the pic on City Racer's website, the VR I purchased from NAPA was a NON-US one and that is why the plug was a little different (black and not green). It wasn't that hard to swap out the plug, and the one from NAPA was only $25, so it was definitely worth it since it was a good deal.

 

[DirtDauberGarage]

Here are a couple pics of the inside...

 

[procomsignathid]

Huge thanks @DirtDauberGarage ! These pics confirm it for me (open to someone telling me Im crazy): the field wire in yours (white green on both harness and regulator) connects to P0, the middle contact that floats between P1 and P2.

This is consistent with all the manuals / diagrams Ive seen thus far, and tells me my P0 contact (red wire) needs to swap sides with my white wire in the plug… Easy fix!

 

[DirtDauberGarage]

Huge thanks @DirtDauberGarage ! These pics confirm it for me (open to someone telling me Im crazy): the field wire in yours (white green on both harness and regulator) connects to P0, the middle contact that floats between P1 and P2.

This is consistent with all the manuals / diagrams Ive seen thus far, and tells me my P0 contact (red wire) needs to swap sides with my white wire in the plug… Easy fix!

Glad to help! This is why I love IH8MUD. What a great resource we have in this community!!

Keep on Cruisin!!