Any body know how to make an alternator on a Dodge 12 valve cummins charge with one wire. I have a buddy who built up a truck, and is on the road between Virginia and New Mexico, and his batts are crapping out. He thinks he can get around 600mi on a pair of batts, but it would be nice if he could get the thing to charge. The alternator originally has three wires. Apparently some of them are used to regulate the alternators output. He currently only has one wire hooked up. He said the dodge comp used something like 4.5 volts to activate the regulator. Any Clues on what needs to be done to fix this, preferably something that can be done at radio shack or the like.

Why not use a voltage regulator from a '70's to mid '80's truck? If the alternator is still good, this method will work well and can be a permanent fix if need be...

He needs to figure out which wire is the wire that excites the alt. Then run it thru a switch mounted on the dash than he can turn on and off. When the swt is on it will charge, and possibly over charge the batteries. He'll have to monitor it and turn the swt off when its overcharging. This should get him home and then he can get is fixed properly.

His big problem, is that he was told that the voltage to excite the alt was around 4.5 volts for some reason. I assume the third lug is a tach wire.

From best I can tell, it looks like there are two wires on the back of the alternator, that generate the field to excite the alternator. One terminal is basically a 12 power, and the other is a ground through the PCM. The PCM turns the ground off and on when needed. So, it seems that a toggle switch could be used as the ground on off, and could be turned on at regular intervals while driving to keep a charge. Like was said above. So, unless someone knows more than I, I will instruct him to make the circuit, and try not to blow up the batts.

and rather than using the stupid switch trick, just buy a voltage regulator for an older dodge and be done with it.

This is a common fix for the newer dodges that have the voltage regulator in the ECU that goes bad from time to time. The regulator will be less than $20, and will be available anywhere, and will wire up just as easy or easier than the switch. Then he won't destroy his batteries either.

what color wire goes where. He said he has a green and a blue. i think he said the blue was heavier guage.

Blue likely should be +12v. That is the color dodge used for the power feed to all their engine stuff on all the other dodges I have worked on anyway...

Blue likely should be +12v. That is the color dodge used for the power feed to all their engine stuff on all the other dodges I have worked on anyway...

Blue likely should be +12v. That is the color dodge used for the power feed to all their engine stuff on all the other dodges I have worked on anyway...

Ok, I'm a retard, it was a light green and a dark green wire, one of them being slightly heavier guage. I am under the impression, that these two wires make a circuit in the alt to excite the alt. Any more thougts.

Anyway, He made it to Memphis Tenn by getting his batts replaced at wall mart every X number of miles. He lost a drive shaft last night, but got that fixed in some mayberry ass town in North carolina. He is around 15 hrs away from albuquerque, and wall mart said that they will not exchange batts after 11:00pm. So he is sleeping in the Wallmart parking lot, and is going to get some batts around 7:00am and he said those new batts will make it here if he drives mostly during the day.

Nice having a diesel truck that requires zero power to keep running during the day just a tank "O" Diesel.

tell him to take a bungy cord and tie the fuel shut off selenoid open then she wont drop and turn off when he looses voltage.

It cannot be run as a one wire setup i tried, i want to say that it is a nip and denzo alternator. I ended up runing the earlier voltage regulator (carry a sspare they like to burn up) dont wire the damn thing incorrectly if you swap the wires tot eh regulator you'll fry the biotch. also there are some alternator shops that for 20-40 can install a small regulator onto/ inside the alternator which worked alto better for me than the mopus regulator idea.

just a thought

Keeping the motor running is not problem, because the truck doesent have a stop solinoid in it right now anyways. He has to open his hood to turn it off right now. His problem is that he cannot run his comp to keep his leakey air bag inflated, and at knight he needs to run lights etc.

But, it seems his journy is coming to an end. Today, he got almost to the border of New Mexico in Adrian Texas. This morning, several injectors wiggled them selves loose somehow, and broke several of the daisy chain return lines. I gave him the suggestion to find a local welding shop, and have little nipples welded on the banjos, and daisy chain all the return lines up with rubber hose. Well, he got that fixed, as well as re torqed the injectors. The engine was running great at this point, since it fixed several leaks etc. But soon after, he tells me that he has run down his last fawking batt, and his air bags are fully deflated, and his front tire is rubbing the body panel. So, once again he was screwed. Just for a not, there is not a Wal Mart anywhere between Amarillo Tx and Albuquerque. So, he cannot return his batts for fresh ones. So, AAA towed him to Tucumcari NM, and was at last report, charging his batts. He was also going to try to hard wire the alternator to a switch or something. I called a Alt shop here in town, and they said that thge two green wires create a circuit, and will make the alt charge. This is what we thought, but we did not want to screw up while he was on the road. So, I have not heard from him in a couple of hours, as I think even his cell phone was out of batts. So, I guess I will possibly see him much later tonight, or maybe tomorrow morning.

Thanks for all the help

Poor Fawker had a week like mine............... :(

How'de it turn out?