Still Stumped - Charging Problems. What would be your next

[heinrich]

Step?

See my old post below. I checked the output of the alternator, and it's a healthy 14.5v. I also replaced the regulator. When I got the new regulator yesterday morning, the light was still on, but still quite dim. Went to work, sat for 6 hours, started the car back up and the "L" light was

now quite bright. I swapped the old regulator back in, and the "L" light was still on, but a dimmer. I switched them back and forth a few times, and there was a definite difference in the intensity of the light between the two regulators. I also noticed that the bottom of the old regulator would get very hot. Anyway, by the time I got home last night, the battery was dead. I rechecked all the connections last night and they are good.

I'm just not sure where to go from here. The only things I can think are (1) it's the battery--which is quite old (but I don't know if that makes any sense) (2) The new regulator I got was actually a bum unit. (30 There's a hidden short somewhere.

What would you do next?

Thanks for any help!

Old Post:

I replaced my alternator bushings last night, and now the red "L" light is glowing ever-so-glimly. So far it's actually so dim that it's hard to see unless it's dark out. The light does seem to get a tad brighter when auxiliary junk like fans is turned on.

The alternator may have gotten a little bump during the process of getting the bushings out and back in. Is it possible this knocked some of the internals in a bad way? I've checked all the connections and the fuses multiple times.

[Mike Self]

connects the alternator with the wiring harness. They have been known to burn out (the wires) up inside the plug where the problem is almost invisible. The plug is supposed to be retained by a wire bail that's often missing on replacment alternators. Otherwise it works loose from engine vibration. The voltage regulator has a similar plug; check it too. Finally, check the heavy brown ground wire running from the alternator case to the engine block. Vibration over the years can cause the terminals on the ends (under the insulator sleeves) to separate from the wires, so it looks good but doesnt' ground very well. No ground wire, no alternator output.

Of course, you've checked battery terminals for cleanlliness, tightness and both ground cables for continuity...

good luck

mike

[monkeystripe]

1) take your battery in to be checked

2) check your battery ground, body to block groud, etc

3) look for the hidden short, which your first stop should be to look where the wires pass through the firewall. over 30 + years the rubber grommet (obviously) disintergrates and allows the wires to rub, causing + side ground. Especially check the wire that is the lead for the charging warning light, its a stupid rare flaw in the 2002, but when that bulb burns out, your alternator wont charge your battery. and of course, you cant tell that its burned out because a fault in the charging system is indicated by that bulb.

[BillWilliams]

1. Charge your battery with a charger, do not count on your alternator to do this.

2. Get your alternator checked, this symptom sometimes indicates a problem with a bad diode

[Tiger75]

There is one in the alt seperate from the voltage regulator on the firewall.

[Jaycen_PNW2002]

I have a 76 I 'll trade you straight up for.

-J

[heinrich]

Thanks for the generous offer Jaycen. How about if we just trade alternators?

[heinrich]

I got a new new regulator to replace the other one I got. No difference. I'm confident it's not the regulator. I replaced the alternator ground wire since the old one was looking a bit manky--although I don't think that was causing any problems either. I also got a new battery. The problem is still the same.

Now, like I said, voltage measured at the B+ pillar is 14.59v. I checked the three-prong plug for continuity at both ends (where it goes into the alt, and where it goes into the regulator. Good continuity on all three wires. With the car running, I unplugged the three-prong plug from the regulator (incidentally, the "L" light went off when I did that) and tested the voltage coming out of the hot wire there. The voltage there read about 11.6v. I'm assuming this isn't right? If I have good continuity on that line, can I assume that there is a problem with the part of the alternator that's going into that plug? Can the alternator be putting out 14.5v and still have a bad diode/triode?

[heinrich]

I took Chris Blumenthal's advice and checked for continuity between the fat red B+ wire at the alternator and the smaller of the two wires going onto the positive battery terminal. Turns out the fat red wire from the alternator had completely broken off of the soldered joint where it joins the two fat red wires in the main harness line. Soldered it back up, and I'm good to go. Thanks again to Chris.

By the way, I'm just keeping the thread up to date in case someone in the future is looking through the archives with a similar problem, and wants to see what happened from start to finish.