...When I unhook the VR, the light goes out. Again, new VR.
Unfortunately, from your next post stating a non-grounded VR, it's very possible that you're frying them as soon as you hook them up.
Yes, some will survive, so I would go ahead and ground it first. Then, if it still causes a drain, replace it.. Again.
Maybe. But like above, get things grounded properly and try again. Maybe you dodged a bullet here, but maybe not. Steve and Viper and some of the others know the proper way to test both a VR and an Alternator, but for now you can try it momentarily to see what you get.
I have three wires going to the alternator, orange, white and black. The orange wire goes to the post with the white plastic washer, white wire goes to post with black plastic washer, and black wire goes to post with red plastic washer.
Orange is "Field" and goes straight to the VR.
White (with a black stripe) is "Stator" and runs the stock electric choke on the carburetor.
Black (probably with a yellow stripe) is the main charge wire and goes into the cab, through the ammeter and then back out to the battery to keep it charged. This is your main power feed to and from the battery.
There is not ground, should there be? It's a 76. I do think it's odd that when I removed the vr it stops drawing.
Yes. The alternator grounds to the engine through it's case, but there is supposed to be a small ground wire connected directly between the case of the alternator and the body of the voltage-regulator. Is there one there?
If you're using the original rubber-encased connector on the back of the alternator, it's connected through one of the attaching rings.
Got pics of this thing?
Okay, went one step farther and removed the three wires from the back of the alternator. When I removed the orange one, the tester light shows zero draw, removing the white and black didn't make any difference, only the orange. Is this because the alternator is bad, or is that the link to the battery through the vr?
Not sure, but I'd say it's the regulator. Someone else might now for sure.
I do have a fiberglass tub, do I need to ground the VR?
Definitely! Not doing so will often fry the new regulator unfortunately. You're not supposed to even connect it to the harness until it's mounted (grounded) to the steel body. In the case of a fiberglass body, you need to ground it with a separate wire to the case.
It may be as simple as running a wire from there to the alternator to simply make sure they're connected together.
But make sure too, that the case of the alternator is clean and the bolt holes mounting it are clean, and the surfaces on the engine that it mounts to are clean and free of paint.
If this is not easy to do (new paint and rusty holes or whatever) run a separate ground wire from the alternator case to the engine where it can get a good connection and make sure it's well bonded to the rest of the grounding system and back to the battery.
With fiberglass, it all becomes more important than ever that the builder (you) makes sure that all paths lead to ground again. The old steel body connected a lot of things together on a common network. The fiberglass swap interrupted that so you need to be uber-diligent in making sure that you create a whole slew of new paths that lead ultimately back to the battery's negative side.
I'm sure I missed things too, so listen to what others have to say about it. Especially those that have glass tubs of their own they had to deal with.
Good luck.
Paul
