uh-oh i'm in trouble

**Nathan289** · June 22nd, 2014, 10:47 PM

Look what I found behind a headliner in a 63 f100 at the junkyard today.
its a movie poster from a drive in from Lovell, WY dated june 1964 .

**Luva65wagon** · June 22nd, 2014, 11:19 PM

Nathan,

For the ammeter to work that main charge wire (Alt to Battery) has to go all the way Alt to the ammeter and then back to the battery.

The charge indicator (dummy light) often doesn't work with a 1-wire setup like ours. I've converted to 3G alternators on both of mine. I use a volt meter as opposed to a light or ammeter, so I've not dug into whether there is a real way to do it or not. Or what it's doing in the first place. When Gene bought his a month ago we asked the guy who sells them how to connect up the light, and he said it doesn't work that way.

I'm guessing a part of the regulator has a component (like a relay) that when there is no charge (key on, engine off) it grounds though the bulb (light on) and when you start the motor and current flows through the relay if pulls the contact open and the light goes out. Just guessing, but that's how I'd do it.

I'll do some digging for you to see if I can't find you an answer to the idiot light with a GM Alt. But to be clear, you have a factory idiot light and an ammeter?

**Nathan289** · June 22nd, 2014, 11:28 PM

Yep. Center gauge is Speedo, odometer, water temp, fuel gauge, oil light, alt light.

Gauge to the left is amp meter as I doubt they'd have 60 volt charging systems.

Gauge to the right is oil pressure.

The amp meter is hooked up to something as it will read a amp draw, flashers on. But when truck is running it doesn't read anything.

I looked at MAD electrical website. You can hook up a dummy light to the gm 3 wire and possibly the one wire if you remove the plug and hook up a wire to the R terminal.

I'll have to look into it more. I found the socket for the light and if I put a bulb in it, it lights up, but doesn't turn off.

I was hoping I could hook the field or the other wire up to the r terminal on the alternator and make it work.

**Luva65wagon** · June 22nd, 2014, 11:38 PM

But the original wires are probably terminated where the old regulator was. Don't know. Wiring hacks are common. Who knows what's what now.

I'll look around for answers, but if you found something to try, you can mock-up right at the ALT. If you can get it to work there first, then trace-back from there to wire it that way at the dash.

**Nathan289** · June 23rd, 2014, 04:28 AM

Regulator and everything has been removed.

I have one wire from battery going to solenoid. I think that where it goes.
then I have one factory plug. Green wire with a stripe iirc and a yellow wire.

I thought they were part of the horn circuit but I fixed that and its not.

This truck is wired different than the ford cars. Wiring is the same color code so far. But its different.

The starter solenoid nis on the back firewall and next to it is a power junction block.

Power from solenoid goes into it and a lot of stuff comes off of it.

I'm going to clean terminal there tonight. I'll take pictures.

**Luva65wagon** · June 23rd, 2014, 10:37 AM

I've been reading on Mad, which is a good resource for GM alternators. I can't find where you said they allow you to connect a charge light. I see a mention that the regulators are the same, but is there a cap to expose that?

Still looking as I can, but pictures help. You may also need to physically trace where wires come from, go to, then return.

**Nathan289** · June 23rd, 2014, 11:11 AM

Maybe it wasnt on mad's website then.

Some where I read you tap into the r terminal. They were also showing an older one wire gm alternator that had a removeable plug on the side that exposes two terminals.

I need to find the charge indicator wire on the truck. Should be yellow with black stripe.

**Nathan289** · June 28th, 2014, 05:45 PM

Roger
Still need to take pictures.. oops..

I did notice something though. The amp gauge will read amp out put while cranking but not when running? Sounds like the alternator is wired to the wrong side of the starter solenoid, except its not wired to it.

On the back firewall is an isolator that has all sorts of big battery cables running to it.. something to do with Ford running all the power through the amp meter then back..

As for my charging light.. it doesn't work because I have power at both wires in the bulb socket

..

Now I'm really concerned.. fireball waiting to happen, maybe?

I need to cut open the harness and figure out were they have the alternator routed too. Sounds like it might be in the wrong spot.

**Luva65wagon** · June 30th, 2014, 11:12 AM

Who knows after all these years. These are so simple to pull, untape, fix, and reinstall - I do it on almost everything I touch. I read somewhere about the way the regulator feeds the dummy light, which might point to having power to both leads, but if I understand correctly - you have nothing connected to the regulator, or don't have a regulator at all now.

Yes, pictures may help.