73 Cj5 1-wire Altenator Swap

Black with white tracer from voltage regular to ground post on alternator
Green with white tracer from voltage regulator to field post on alternator
Large main postive post of alternator to starter main positive post, heavy gauge red wire #10 gauge!
Tan from voltage regulator to small positive post on alternator
Tan (exciter) from small positive post on alternator, to ignition switch
Heavy gauge red wire also off large positive post of alternator runs to the main breaker on your light switch.

 

I would suggest to buy the wide pully for your alternator so your can use the factory 1/2" wide fan belt that Jeeps have on them. That way you still can use the factory Jeep fan belt. Good Luck.

 

Thank you for your replies Beach66Bum, if you have time, please reference the attached photo of the schematic that came with my wiring harness, this is the source of my confusion, as the color of the wires do not match what is factory, and since I have the alternator on the left, as you can see from the numbering on the right, there is no mention of attaching the voltage regulator/exciter wires.

https://imgur.com/a/ABsTJ4Z

 

https://imgur.com/a/ABsTJ4Z

 

I use a 1 wire in most of my vehicles, including my Diesel CJ2a that will not rev faster than 3000RPM. haven't ever had problems with them. I do ground them really good, I put an extra ground strap going from the alternator case to the engine block. Maybe that helps, I don't know, but it's always worked for me. So it's a 2 wire

 

Thanks Danielbuck, I have read about the one wire alternators, that's my plan B, since I have a new alternator now I'd like to try to make it work, again, thanks for your reply to my post!

 

I used the three wire 12SI alternator as it made sense to do so. The 12SI has a better cooling fan and eliminates having an external regulator. Clocked alternator for my use. The alternator
is grounded to the block. Also added a double pulley and belts as I had the pulleys to do so. Added the Ford style starter solenoid so there is not a continuously hot wire running to the starter.
Fuses, fusible links or breakers are recommended to keep wiring from burning up.
A good read on alternators if you have not seen it. http://www.madelectrical.com/index.shtml

 

Another advantage to the 3-wire is still being able to use the 'Alt' light in the gauge cluster. You can't really do that with a 1-wire and would need a volt meter to monitor if it's working or not.

 

I have both of those as redundancy?

 

Again, thank you all for responding to my question(s). I purchased the mentioned GM one wire alternator, but, at what point does the ignition become energized on my Walcks replacement wiring harness? I isolated all the wires from the wiring harness attached to the previous alternator, both at the alternator end and the ONE small gauge red wire that ran to the battery post on the alternator. I ran a 4 gauge wire from the new one wire alternator down to the battery post on the starter. Now nothing, I have no power at all, the battery is charged, but no cranking, no headlights no anything.
What am I missing?

 

It sounds like the small red wire is what feeds your ignition switch. You'll need to hook that back up.

 

Original diagram. Not sure on the colors.

 

Thanks Fireball, I'm wondering though if I need to run a wire from the starter battery post directly to the CJ5 head light switch which I am still using, that is the main power distribution point, the only one in fact.

 

Thanks John, that helps. the schematic from Walcks was all black, and reduced in size, so the lines were difficult to track. So, it looks like I need to route power to both the ignition switch and headlight switch from the alternator from your schematic. The Summit alternator has one post that I have connected to the battery post on the starter with a 4 gauge wire.
Is the 1 wire alternator actually going to be a 3 wire?
Do I need to not only reconnect the small red wire down at the alternator so the solenoid is signaled from the ignition switch, but also the red wires that came with the harness near the alternator at the 1 wire alternator power post?

Thanks all for your help!

Dave

 

This is a 3-wire diagram which will function with the alternator light. On a '70 CJ the large red goes to the large starter terminal along with
a hot wire to the battery. A wire then comes from this same junction to the headlight switch as the next junction and on to the ignition switch.
The junction shown in the diagram can be considered the starter terminal.The #2 wire off the alternator is the sensing wire to tell the
alternator to charge and senses the voltage at that junction where the loads are located farther from the alternator. This is why a 3-wire is
and allows the function of the charge light/indicator. If using a 3-wire without a charge light, a diode must be in the #1 wire to prevent
engine from staying on do to feedback from the alternator. I used both on mine. Note the ground on the starter. There is usually a threaded hole to
hole to attach a ground lug and wire to on the alternator.
Some alternators come as a 1 or three wire. There may be a jumper plug or just a plug where the #1 and #2 wires go or there may be nothing
there at all. The 1-wire does its sensing of voltage internally and only senses the output at the large bat. terminal. It is a close feedback loop and
does not care what voltage/current is furter out in the circuit.
Clear as mud now, right? Any other question, comments, go ahead.




u

Wire size chart to battery or main junction for alternator size. This is the wire length from the alternator to the first junction point.



One wire diagram not using a charge indicator light. This would be more like a one-wire in a CJ. Note the 10 gauge wire from the starter solenoid
going to the ignition switch. A CJ wire goes to the light switch and on to the ignition switch which makes no difference to the power. Every load in
the Jeep is off that 10 gauge wire. Lights, starter solenoid, heater fan, wipers, etc.
Replaced diagram with a video.

 

FYI: The charge/indicator light must use an incandescent bulb; an LED bulb does not create enough load to trigger the alternator to charge. The engine will have to rev to approximately 1500 RPMs or more before the alternator will start charging. Don't ask how I know .

Martin

 

Thank you all for your replies to my question, the problem is resolved.
I used the above linked Summit 100 amp one wire alternator, there is a 4 gauge wire connecting it to the battery post on the starter. I had no power initially, but using a continuity check, I found that I needed to connect the power wire that goes the the original headlight switch also to the output post on the one wire alternator, so it's now a two wire alternator. The Dauntless is now charging at over 14 volts as checked at the battery.

 

That is great. It doesn't matter whether that wire goes to the alternator or the starter as it was originally.