No Gen light and no charging....

[SGB]

I'm perplexed by charging problems.
I've taken my alternator out 3 times now.
It has been tested twice. Its back in the car now.

I rebuilt my relay board and all the connections are good per continuity testing after the new filling cured.

I put it back in.

The "Gen" light usually doesn't function.

I've tested the circuit (light blue wire fyi; runs from position 2 on the back relay board multi-pin connector thingy all the way to the infamous fuse 9). On the relay board, (more fyi; It runs straight to the D+ terminal of the voltage regulator, which is also directly connected to the D+ terminal of the wiring harness from the alternator) all the way to the bulb. Its good. So is the bulb..

I've got two voltage regs, and I got occasional function (ie; red light during startup that goes away when the engine fires up) when the bus one is plugged into the relay board. The big stock regulator (new I might add, so it ~should~ work) always leaves the gen light unlit.

When I read the trouble shooting article it says, "connect +12 volts from the batteryto the DF terminal of the relay board" Is that with the VR unplugged? How else can you get to that pole? then it says, ""this should result in maximum output of the alternator." Whaddayasayinhere? Clip these togeter with a jumper and start the car? Will it hurt alternator to run with VR? I'm guessing that this bypasses the bulb to provide full initiating charge. I think.

I'm really puzzled.

The alternator harness is new (Thanks Jeff Bowlsby).

The alternator is tested and retested.

The connector pins and jacks have all been scratched and scuffed and sanded on even thought they looked OK.

All the grounds (engine by relay plate and inside behind fuse panel) have been cleaned and recleaned.

Fuse nine replaced. All fuses and fuse holders brushed up with sandpaper.

Q: Where does the alternator get its ground? Through the engine and ground strap? Is this the ground for the gen light during startup?

Q2: Where does VR get its ground?


Aaaaargh!

I can't get that gen light to light anymore again. Whaaaah.

Ideas?

Where should I start the next round of DO-OVER AGAIN! ?

[Dave at Pelican Parts]

Let's see... The alternator grounds through its case to the fan shroud. Eventually grounding though the tranny ground strap. The VR gets its ground from ... Hmm, possibly the outer casing? Not sure on that!

I do know that when you have a regulator that is not plugged in, the light will not go on and you will get no charging of the battery. I'm suspecting that your new VR is bad...

Yes, in the article you unplug the VR and short those two leads together. It shouldn't hurt the charging system to run that way for a short time--over the medium-term it can boil your battery, though.

--DD

[ws91420]

Check your local flaps. They may be able to test the VR on bench out of car.

[SGB]

OK thanks Dave. So if I get good charging when I jump the VR like that, it will be a pretty sure sign....
I was about to start taking tin off again.
I don't think the VR is grounded through the case.
It screws into the plastic part of the relay board. No electrical contact.

[SGB]

Tests complete-
alternator output 16V.
bulb circuit checks.

Hope a new VR does the trick. I'll get this one tested and another new one tomorrow I hope.

[SGB]

Yep. Voltage regulator. Bought it in May.....
What would (or could) cause failure so soon? Seems like if it was defective it would have never worked or failed as soon as a load hit..
So all is really well now.
In the process of replacing the VR, I discovered:
-bad shift linkage bushing
-leaking speedo drive O-ring
-2 missing exhaust studs (!!)
-loose speedo drive cable bolt
-overheated, dried up broken insulation on the alternator wiring harness
-surprisingly coroded grounds
Each of these could have left me stranded.
-wow-

It was really a good thing.