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Mexican 1992 Dodge Spirit no charge from alt

Here in Mexico they call it a Chrysler Spirit, but I assume that means Dodge Spirit. 1992. Battery is ‘new’ but losing charge, now car will not start, I have my old charger on it. The battery meter when she drove it home was very low which agrees with no output of alternator.

Alternator hot lead is battery voltage so I assume fusible link is good.

With key to operate, there is no voltage on either of 2 smaller leads on the alternator as measured to - battery lead. Should there be or will this only appear to a voltmeter when the car is running (relay or whatever)?

I think there should be a fuse for the ignition to regulator, but the manual does not list that function though it is in Spanish, so I might miss it, but don’t think so.

While I wait for a possible answer, I may look at fuses, maybe pull and measure them and keep Googling.

Thanks for any tips.

Let me add that a quick check of lights showed they generally work.

I just realized I have Haynes for the Dodge mini-vans, in Spanish. I will attempt to extrapolate from it as to where a fuse for the regulator might be.

Oh, oh! The Haynes for Caravan shows at least 5 fusible links behind the battery, whatever that means. If there is not a fuse, and none is listed that would seem like the best thing to check if I can figure out how to do it. I know the fusible link to the output of alternator is okay, because there is battery voltage on that alternator connection. The wiring charts are not real good, so it is going to be a guess.

I think the voltage regulator is built in to the engine computer on that car. It may be hard to find a reference to it except in the factory shop manual.

Do you have the 4 cylinder engine?

As dumb as it sounds, I did not notice the number of cylinders, because I was concentrating on the electrical problem at hand. I will look when she gets home. I am hoping there is an obvious burned fusible link when I get to look at it.

Voltage regulator in the engine computer? Wow! That is not intuitive.

It looked like a standard alternator, with the main output lead, and the other two small leads as on a voltage regulator alternator.

I did come up with a partial wiring chart on a URL. But, it doesn’t show the entire charging circuit. It was pdf, I converted it to JPG using ‘convert’ from Linux ImageMagick, in hopes of shrinking it to be printed, it was like 5,000 x 5000 pixels, at 800 x ? it shrinks the pieces so small that printing it, it becomes illegibly small. I may have to GIMP it into sections, print them, and tape them to a full sized lay out. Until then I will be forced to use the computer picture.

I will be looking at the diagrams with your tip in mind. That sure seems like a bad decision to put something like the voltage regulator in an expensive engine computer, doesn’t it?

Thanks. She was not home just now. In this little Mexican village, women walk their little ones to school and pick them up later. Not so much the bogus fear of the evil male as in the US, but cars; trucks, and dogs that might be aggressive. I think she stays as a volunteer during the school time so I must wait until she gets home.

That didn’t take long. A few seconds with Google, and there it was.

Said the regulator is in the SBEC (Single board Engine controller) and is the most common reason the SBEC needs to be replaced. Sounds like most of us would say that is what we call the engine computer.

It also says one can fix it with an external regulator. IGN to ignition switch; FLD to either field wire on alternator; ground the other field lead on alternator. Connect base of regulator to - lead of battery. Put a resistor, did not say what size or value across now unused leads from computer to keep CEL from coming on, and secure all wires to keep from being damaged.

Those computers can run nearly 500 dollars USD here, so I am betting if that is the problem, he will attempt to use an external regulator. Heh, heh.

He is a EE who teaches at a local technology school. I wish I could say that meant he is a genius like the many engineers I worked with over the years. But, until I meet him I can’t say that. But, he should be able to install an external regulator.

His wife did say he once replaced the fuel pump, which is a very good sign in his favor.

Disconnect the wires for the field windings, and check for resistance. If it is in specs, the problem can be a bad circuit in the ECM. I had good luck fixing a friend’s Voyager minivan when this happened to her. Purchased a separate external voltage regulator and a pigtail harness. The harness was color coded for the green and blue wires for the field windings. I tapped the blue line for a 12V reference and cut the green line to splice to the pigtail. Used a couple of sheet metal screws to fasten the regulator to a good sheet metal ground. Worked like a charm.

Here are nice, simple, diagrams of the alternator circuity: Give the diagrams about five minuets to download. Scroll down to Fig. 78 and on.

That link did not take me to any such page. I had to register then work my way down to the charging circuits. They were definitely the thing I needed. Clicking on the link after logging in did no take me there, either. But, I got what I needed, thanks.

Other URL’s said the computer operated the field winding. However, this schematic plainly shows one side of the field connected through the ignition switch. The other side to pin 20 of the computer.

So, the computer only controls the current through the field.

In this car’s case, clearly, there is something wrong with the circuit from battery to ignition switch, to field connection. He will need to check the fusible links, also if they are good, the switch itself.


Interesting. Well, we all have to have our noses rubbed in our own misery from time to time. Hee, hee. I went back and copied and pasted the link into the browser window, and this time it took me there. Sigh!

Sometimes I/we tell people to register at, sometimes, I/we don’t. I don’t know if those who don’t say they couldn’t reach the link tried, or not. Should we tell everyone, “You’ve got to register at that site; then, return here, and click on the link, again.” ? Silence carries little feedback.

It works. Once he saw the connections, direct from battery to ignition switch, from switch to one side of the field connection, and realizing following those wires was extremely difficult, he methodically unplugged all the connectors by the air filter, examined them, and put them together again.

He also disassembled, I think I would say, all the connections to the positive battery lead and cleaned them.

And, when he had it all together again, it worked. Voltage from the alternator goes to 14 volts or so, charge meter is back to normal.

He also checked, and yes, one field lead now has battery voltage like it should.

I did get my meter back, and my Dodge Caravan manual, and told him to keep all the printed pages if he wished. I have them saved on one of the Linux Desktops.

It was a good day, IMO. He got it fixed even if we will never know what actually did the job. His wife gets to drive again instead of walking the kid the 1/2 mile to school. And, it cost him nothing except his labor.

He said he will take it out for a test drive.

To me, the good news is with your help, and some blundering on my part, I did find the diagram he needed, which pointed him at the general area, and his brute force actions fixed the problem. Plus he has some wiring charts. As I said below, it was IMO a good day. An experienced mechanic might have fixed it in minutes, but out here in the Third World there aren’t many of them. (i.e. - none.) It is a long drive to a good mechanic.

Actually, what confused me was after I registered and logged in, I did go back to the link, and it didn’t work. Like his cleaning and plugging and unplugging, we will never know why, but since it works, we are all happy.

Plus two men who didn’t know each other before, now do. Heckuva’ great day. Thanks a million.