I got a shock (bad pun) when I drove home from work yesterday and my headlights got dimmer...and dimmer...and gone! Just about a mile before they guttered and died, strange lights began to appear on the dash, like the seatbelt light, and then the engine started misfiring. Then nothing. Dead in the street at the end of my driveway.

Got a new battery, new cables, new (rebuilt) alternator, and no fuses are blown. The voltage regulator "looks" new (you now how that goes, it's a Wells). It may be that the truck was running off just battery power, and the alternator either isn't putting out enough power, or..sheesh, I don't know. The ammeter doesn't show charge or discharge when it is running, but it used to.

Any ideas?

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If it was easy, everybody would be doing it.

It sounds like you've already got the diagnosis pretty well worked out in your head: No charging. Time to break out the voltmeter and do some testing. Start with the info in this thread.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Usually if you start seeing other dashlights or "all of them" at the same time, it means you've lost the ground to something major (had that happen when the headlight ground broke), so the path to ground can be back through the dash or some other path of least resistance.

-D.Idiot

Thanks, Dan! As usual, you are the font of knowledge and reason.

With a fresh battery, at idle, I am getting a steady 13.8 volts at the alternator but only 11.5 at the battery by the time it gets there. I checked for corrosion at the terminals, and cleaned it off. No change.

So, am I looking at a voltage regulator, perhaps? I am not really keen on wells products.

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If it was easy, everybody would be doing it.

If it were the regulator you wouldn't be measuring a typical 13.8 at the alternator. Infact, getting 13.8 at the alternator tells you the alternator <-> regulator circuit is ok.

Start at the thick charging lead coming out of the alternator and follow it back. Check the bulkhead connectors, the amp gauge connectors. Alternatively you can start at the battery + terminal and go the other direction. One thick lead goes to the starter, but another goes to the starter relay and branches to the bulkhead to feed the rest.

It sounds like your set against replacing the regulator - don't do it yet because it seems to be working at the moment. Once the kinks have been worked out and everything is operational, then you can replace it. Don't introduce any more variables into the mix then need be.

Thanks! I know just enough about electricity to hurt myself. I read a little about the "ammeter bypass" from mad electrical and it really has me intrigued. That might be a project for another day.

Right now I need to get this ting going. While all the connections "seem" to be fine, the 10 gauge wire coming out of the alternator is crispy when I try to move it. I'd say that must mean it is old and brittle, or burned up, or a little of both. I had to rip the factory non-adhesive tape off to find this out.

So, thanks Dan and Pierre for saving me some unnecessary $ outlay. It has to be some sort of corrosion some place. And of course, a record 200 year flood has made it really humid here lately, so I'm sure that isn't helping one bit!

Got any idea of what's good to clean these contacts and terminals?

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If it was easy, everybody would be doing it.

MAD electric is a site ignorantly written about Mopars by a Chevy-head. Ignore it, number one. Number two, the ammeter bypass thing doesn't apply to your truck, which has an external-shunt ammeter.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

This site has some wiring diagrams. What car is this for? Username says 64 but your sig says 1984. Site doesn't go that late, otherwise you'll have to get a service manual and look at the wiring diagram. It spells out where all the connections and splices are.

Just going off of memory - the wire comes out the alternator, through the bulkhead connector, to the ammeter. Then other post of ammeter goes back to the bulkhead, to the starter relay/solenoid, then to battery. There are splices along the way to feed the ignition switch, fuse block, etc but thats the basic path for the heavy gauge wire.

Did you actually pull apart the bulkhead connectors to look at them? They make contact cleaner but you don't need to get that fancy - some medium grit sandpaper or the end of a small flathead screwdriver will suffice.

ok, now I seem to be going backwards trying to fix this thing. I cleaned all the connections with 5% acid solution, including the bulkhead connector. Now I get 11.56 volts at the alternator, and slightly less at the battery while it's running.

I charged the battery and let it alone for 2 hours. Sure enough, the voltage dropped from 12 volts to 10 in that amount of time. I've got a circuit draining the battery some place.

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If it was easy, everybody would be doing it.

Sounds like a bad cell in the battery,if you had battery disconected from the truck during the charge

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V8?? We don't need no stink'n V8!!

Yikes. That wasn't wise. Acid applied to wires will come back to haunt you sooner than later.
Either that or your battery has a dead cell. Measure the current draw with everything electrical on the car switched off and the doors closed (dome light), etc. If there's appreciable current flowing, then yeah, you do have something draining the battery. If that's what you find, pull fuses one at a time and repeat the test until the current draw goes away - then you've found the culprit.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Can the alternator drain a battery? I swapped for one of known quality and the problem went away. :shrug: I bought a new one and so far, so good.

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If it was easy, everybody would be doing it.

It can if it has an internal short... Glad to hear you got it fixed.

Mike

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