62 wiring help. Convert to Alternator

[LuckyDSquared]

I have a bastard 62 truck and everything I search for is relevant to 63 and up I can only assume. I’m finishing up a swap from the original I6 to a SBC with a 3 or 4 wire alternator. My question is how to wire it up?

I currently have one larger contraption inside front of engine bay with three prongs, the top have the main positive lead from the battery, the middle has to be some sort of ground and has one wire that runs to generator, the third bottom prong and another lead from the generator. There are some smaller wire also installed such as a smaller wire from generator and one smaller wire that went to generator light on instruments. The smaller contraption below has three wires, green smaller wire that runs inside near the ignition switch (unfused) I assume is the horn signal wire, and a positive red wire from the larger contraption above it and one third wire I can only assume went to the horn (never hooked up and went to nothing when I got the truck).

One contraption is a horn relay and the other is the voltage regulator. All diagrams I’ve seen so far has four wires from generator and 4 wires to regulator. Also, the colors don’t match. Any help is appreciated. Even if somebody just has a 62 wiring diagram it would be much appreciated.

[LuckyDSquared]

I wanted to post some pictures of what I have on my truck versus what all the previous threads refer to. The first picture is a 4 wire regulator like old post refer to. The second picture is of what my truck has.

[ray_mcavoy]

Yes, the larger of the two devices is the voltage regulator, smaller one is the horn relay.

The voltage regulator used with the generator does have 3 terminals (ones used with the 63+ externally regulated alternators have 4).

The 3 terminals on the generator style voltage regulator are:
B (battery) terminal -- Has a black wire that connects to the + battery terminal, a red power feed wire into the cab, and a red power feed wire to the horn relay.
A (armature) terminal -- Has a brown wire that connects to the "A" terminal on the generator and a red wire that runs inside the cab to the "GEN" light.
F (field) terminal -- Has a dark blue wire that connects to the "F" terminal on the generator.
There is also a black ground wire connecting from the voltage regulator mounting bracket to the "G" terminal on the generator.

To convert over to an alternator, you first have to determine if it's an internally or externally regulated alternator (there are both styles that use 3 wires).
An internally regulated alternator is probably the easiest to hook up and will involve:

(1) Remove the old voltage regulator and eliminate the brown & blue wires that used to connect from the regulator to the generator.

(2) Add a junction stud or junction block at the former voltage regulator location. Connect all 3 of the wires from the old regulator's "B" terminal to this new junction. Also run 2 new wires from this junction to the new alternator. Hook one to the alternator's output stud and the other to it's voltage sensing terminal.

(3) Connect the red "GEN" light wire (that used to go to the regulator's "A" terminal) to the new alternator's warning light terminal.

[LuckyDSquared]

Originally Posted by ray_mcavoy

Yes, the larger of the two devices is the voltage regulator, smaller one is the horn relay.

The voltage regulator used with the generator does have 3 terminals (ones used with the 63+ externally regulated alternators have 4).

The 3 terminals on the generator style voltage regulator are:
B (battery) terminal -- Has a black wire that connects to the + battery terminal, a red power feed wire into the cab, and a red power feed wire to the horn relay.
A (armature) terminal -- Has a brown wire that connects to the "A" terminal on the generator and a red wire that runs inside the cab to the "GEN" light.
F (field) terminal -- Has a dark blue wire that connects to the "F" terminal on the generator.
There is also a black ground wire connecting from the voltage regulator mounting bracket to the "G" terminal on the generator.

To convert over to an alternator, you first have to determine if it's an internally or externally regulated alternator (there are both styles that use 3 wires).
An internally regulated alternator is probably the easiest to hook up and will involve:

(1) Remove the old voltage regulator and eliminate the brown & blue wires that used to connect from the regulator to the generator.

(2) Add a junction stud or junction block at the former voltage regulator location. Connect all 3 of the wires from the old regulator's "B" terminal to this new junction. Also run 2 new wires from this junction to the new alternator. Hook one to the alternator's output stud and the other to it's voltage sensing terminal.

(3) Connect the red "GEN" light wire (that used to go to the regulator's "A" terminal) to the new alternator's warning light terminal.

Perfect. Thanks for that bud. Dumb question, but the ground wire from the old generator also gets eliminated since the newer alternators are internally grounded?

[ray_mcavoy]

You're welcome!

The alternator case is grounded to the engine block via it's mounting brackets. And the old generator was as well.

The purpose of that ground wire was to provide a good ground for the regulator, horn relay, headlights, etc. attached to the front sheetmetal.

Starting sometime around 64 I think, GM changed the location of the front sheetmetal ground wire and ran it to the negative battery terminal instead of the generator or alternator case.

So if you have the later style negative battery cable assembly with the ground wire going to the front sheetmetal, you won't need that ground wire. Otherwise, you'll want to keep it in place. Some alternators have a ground stud. Or you could attach it to one of the alternator case bolts, mounting bolts, etc.

[LuckyDSquared]

Originally Posted by ray_mcavoy

You're welcome!

The alternator case is grounded to the engine block via it's mounting brackets. And the old generator was as well.

The purpose of that ground wire was to provide a good ground for the regulator, horn relay, headlights, etc. attached to the front sheetmetal.

Starting sometime around 64 I think, GM changed the location of the front sheetmetal ground wire and ran it to the negative battery terminal instead of the generator or alternator case.

So if you have the later style negative battery cable assembly with the ground wire going to the front sheetmetal, you won't need that ground wire. Otherwise, you'll want to keep it in place. Some alternators have a ground stud. Or you could attach it to one of the alternator case bolts, mounting bolts, etc.

Again, thanks.

Last question...if I eliminate both the regulator and horn relay I can wire in typical modern relays for a horn, fuel pump, fan, etc. from the new junction without any problems, correct?

[ray_mcavoy]

Yes, you could replace the stock horn relay with a modern one. And yes, the junction block can be used to supply power to additional relays for an electric fuel pump, fans, etc.

I'd recommend using some fusible links or fuses (maybe even add in a little fuse block) to protect each of the added relay circuits that will be drawing power off the junction. And of course make sure to use a suitable gauge wire to feed power from the alternator to that junction. The existing wire running to the positive battery terminal will likely be okay unless you plan to run some heavy loads with the engine off. Adding a fusible link to the end of that wire (near where it attaches to the battery) is a good idea too (GM started doing that as factory equipment in 67).

[Angrywood]

Originally Posted by ray_mcavoy

Yes, the larger of the two devices is the voltage regulator, smaller one is the horn relay.

The voltage regulator used with the generator does have 3 terminals (ones used with the 63+ externally regulated alternators have 4).

The 3 terminals on the generator style voltage regulator are:
B (battery) terminal -- Has a black wire that connects to the + battery terminal, a red power feed wire into the cab, and a red power feed wire to the horn relay.
A (armature) terminal -- Has a brown wire that connects to the "A" terminal on the generator and a red wire that runs inside the cab to the "GEN" light.
F (field) terminal -- Has a dark blue wire that connects to the "F" terminal on the generator.
There is also a black ground wire connecting from the voltage regulator mounting bracket to the "G" terminal on the generator.

To convert over to an alternator, you first have to determine if it's an internally or externally regulated alternator (there are both styles that use 3 wires).
An internally regulated alternator is probably the easiest to hook up and will involve:

(1) Remove the old voltage regulator and eliminate the brown & blue wires that used to connect from the regulator to the generator.

(2) Add a junction stud or junction block at the former voltage regulator location. Connect all 3 of the wires from the old regulator's "B" terminal to this new junction. Also run 2 new wires from this junction to the new alternator. Hook one to the alternator's output stud and the other to it's voltage sensing terminal.

(3) Connect the red "GEN" light wire (that used to go to the regulator's "A" terminal) to the new alternator's warning light terminal.

i realize this is an old thread.. but Ray... i used this method and the GEN does not work now. any ideas or troubleshooting thoughts? 1962 c10 SBC 327, 12SI 94 Alt. cant figure it out. thnx

[ray_mcavoy]

Originally Posted by Angrywood

i realize this is an old thread.. but Ray... i used this method and the GEN does not work now. any ideas or troubleshooting thoughts? 1962 c10 SBC 327, 12SI 94 Alt. cant figure it out. thnx

When you say the "GEN does not work now", do you mean the GEN light on the dash doesn't work now?

If so, make sure you have correctly identified the terminals on the alternator. For the 12SI you're using, the GEN light wire should be connected to it's #1 terminal. The terminals are usually marked with the numbers "1" and "2" cast into the housing near them.

Also, check with the company where you bought the alternator to make sure it doesn't have a "1-wire" regulator. I don't think those regulators will operate a warning light. Those usually have the 2 small terminals capped off with a plastic or rubber plug but that might not always be the case.

Finally, you can check the GEN light by temporarily disconnecting it's wire from the alternator and touching that wire to ground. That should cause the GEN light to come on when you turn on the key. If not, check for a burned out bulb, bad connection, broken wire, etc. in the GEN light circuit.

[Angrywood]

Originally Posted by ray_mcavoy

When you say the "GEN does not work now", do you mean the GEN light on the dash doesn't work now?

light worked with the gen set up. does not work now with the alt.

If so, make sure you have correctly identified the terminals on the alternator. For the 12SI you're using, the GEN light wire should be connected to it's #1 terminal. The terminals are usually marked with the numbers "1" and "2" cast into the housing near them.

Also, check with the company where you bought the alternator to make sure it doesn't have a "1-wire" regulator. I don't think those regulators will operate a warning light. Those usually have the 2 small terminals capped off with a plastic or rubber plug but that might not always be the case.

Finally, you can check the GEN light by temporarily disconnecting it's wire from the alternator and touching that wire to ground. That should cause the GEN light to come on when you turn on the key. If not, check for a burned out bulb, bad connection, broken wire, etc. in the GEN light circuit.

the wires and terminals are confirmed. it is a 3 wire Delco Remy but will confirm with the manufacturer about the terms.

i know the bulb works and socket works. i will try the wire to ground and see what happens. thanks for the info

[vince1]

Which alternator are you going with? I've got a 10si in one vehicle and a cs130 in another.

Here's some info if you want to go with the newer style CS130.

https://www.rockauto.com/en/catalog/...generator,2412
https://www.hemmings.com/blog/articl...0-alternators/

[forestb]

This is what I was using before I had all my wiring redone. It makes the conversion vary easy.

https://americanautowire.com/product...l&_ss=e&_v=1.0

[Angrywood]

I took the gen wire and grounded it, turned the igintion on and still not gen light. looks like ill be going forward with getting a dash wire harness. too much splicing and dicing going on under the dash to try and figure it out. so mise well clean it up. but now my starter quit working.... everyday something new.