12V wiring diagram

"Field 1" port needs +12v from the battery. Current limited by either a resistor or incandescent light bulb. In-line.  This provides excitation to the alternator. Without it there is no magnetic "field". Just spinning metal. This does not apply if you have a one wire alternator. They are self exciting. 

What is "VR"?

VR= voltage regulator

CJTWOA wrote: II notice lots of people are talking about buying a wiring harness. I'm working on a tight budget and I was thinking about finding some good diagrams/info and using 16 and 12 gauge wire. Is that a bad idea?

Its not a bad idea if done right, lots of members here have built their own harness.
It really comes down to what you want in the end, if you are going 12v and want a fuse box (a good idea)and add accessories, a custom harness is the way to go. For me it made sense to just buy one, the cost of supplies was going to be half of a made harness, but I wanted to stay original and with the cloth.

Like this:

Everything except the starting circuit has been omitted due to extreme laziness



I don't remember which terminal it is on a 4 post solenoid, or you could use a three poster.



Edited by LesBerg - 22 June 2016 at 5:19am

Thank you guys - I'm still working at this - all this and I'm pretty sure my coil is bad - most likely going to get one with an internal ballast resistor instead.

I don't know if this will help you or not but here's a wiring diagram I drew up for a DJ3A. At least some of the circuits should be similar.



IF I understand correctly with a internally resisted coil you shouldn't need a ballast resistor.

My motor was originally piece together wired for 12v, now converted back to 6. Originally had a 6v coil W/ ballast resistor on the firewall to work for 12V. Originally had a 4 post (wrong) solenoid. On the two smaller posts at the top of the solenoid only the small post nearest the passenger side fender was used. The other post had no wire hooked to it at all and it would crank and run.



Charles

It would take a better wiring expert than me to completely answer your question.   I only know how my DJ was wired to run on 12v and it worked fine that way. Both cranking and charging.

I'm definitely not sure of the particulars of the entire function of a four post solenoid or how the bypassing (which I have heard ) of actually works and I don't dare want to mislead you there.

The last thing I think I KNOW is when I wired mine back up for 6 volt I changed back to a 3 post 6v solenoid and did away with the resistor which I discovered was required for only for a 6v coil when converted to 12 volt.    I 'think' a 6v coil actually puts out about 9 volts but don't hold me to that either. I'm far from a wiring expert. That's why I spent so much time making that drawing. My eyes aren't that great and I made my own wiring harness.



But I am pretty sure during my research that a internally resisted 12v coil doesn't require a external ballast resistor at all ....just don't leave the key on when the jeep is not running. This would hold true for either 6 or 12v because then you're in danger of burning up the points.

Later when I get home I'll look up a actual 12v wiring diagram for a DJ3A and we'll see what' kind of solenoid it requires. 3 post or four post.

Charles



Edited by PapaC - 24 June 2016 at 6:47pm

CJTWOA wrote: Thank you Charles! So a 4-post solenoid is the wrong solenoid? I was under the impression that with a 4 post solenoid you can send that 4th post - (the I post) - can be sent directly to the (-) on the coil to send full power to the coil during initial start at key turn (bypassing the ballast resistor momentarily). After that once the key springs back to run position the "I" post looses power (along with the starter pole) and then the power from the Run position on the key takes over and runs through the ballast resistor at a reduced voltage. Maybe this thinking is why I'm having issues.

I believe you're correct on how the four-post solenoid works, but I'm not positive. Whether or not it's the 'correct' one is based on how you wire up the system.

If you want the four-post and intend to wire it in the described fashion, then it's the correct part.