volt meter connections

[akzale]

Running wires for my gauges, and I'm stuck on the volt meter. Back of the gauge has 4 terminals. One for a ground, one for the illumination,(from light switch) one for a battery or 12v supply,(from battery terminal on ignition switch) and one from the "sending unit".
Can't seem to get the wiring right on it. It isn't reading any voltage at all. Not sure why I need 2 12 volt terminals, but I'm not an electrical guru, so maybe I do. Appreciate any input!

 

[HenrysT]

What brand / model is your voltmeter? Looking up several wiring diagrams, two wires are for lights (pos. & neg.) and one switched pos. (from ign. sw.) and the other is ground, these two wires are usually heavy(er) gauge. Get back to us with the make/model!

 

[choppedtop]

Never heard of sending unit for volt meter. You don't want to go directly from battery terminal on switch because that would be a constant drain on battery. Use the switched side for volt meter. Need to learn more about this type meter.

 

[akzale]

Never heard of sending unit for volt meter. You don't want to go directly from battery terminal on switch because that would be a constant drain on battery. Use the switched side for volt meter. Need to learn more about this type meter.

It's an aftermarket brand that I bought online. Maybe that's the problem!!

 

[choppedtop]

Did you try just hooking to a battery? Ground to Neg/pos to Hot. I know you know that. Forget the other terminals for the test. If it is working you would/should show around 12.6 to 13+ volts. The sending unit terminal is a puzzle to me.

 

[PotvinGuy]

Volt meters do not have sending units. I think you have some other meter, like oil pressure or water temp. Can you post a pic of front and back?

 

[fletcherson]

Unless it requires the sensor wire from the alternator, I have no idea what it would be.

 

[akzale]

Tried to post a few pics, but couldn't upload them. I'm going to try running a wire from the battery terminal on the alternator to the "S" (sender) terminal on the gauge. I'll use a switched 12V terminal from the ignition switch to the gauge (and back to the starter) I'll let you know how it turns out.
Thanks for the replies, really appreciate the input.

 

[Neshkoro]

Be careful where you apply that hot wire. You don't want to fry the gauge.
How about putting a temporary fuse in line to protect your experiment?
Sparks and fire is not your friend.

 

[akzale]

Be careful where you apply that hot wire. You don't want to fry the gauge.
How about putting a temporary fuse in line to protect your experiment?
Sparks and fire is not your friend.

No sparks, please, no sparks!

 

[JeffK]

Sounds like you have a boat gauge. From another forum:

There are 4 terminals on OMC volt gauges that I am aware of..

1. I = Ignition

2. G = Ground

3. S = Sending Unit (I believe)

4. Unmarked = Light

You put the Purple wire, I had Violet, on the I terminal...
You put the Black wire on the G terminal
And if you want lights, the Blue wire goes on the Unmarked terminal where the screw in light socket is...

The S is not used for this gauge as it does not need a sending unit. If you have a trim gauge, look at it and there is a wire from the trim tilt sending unit hooked up to the S terminal

 

[akzale]

Thanks for all the input. Lots of smart folks who took the time to reply with suggestions and offer encouragement. I had another local rodder come to my rescue. He twisted up the wires and everything is cool!
My problem was kinda embarrassing as I was wiring up the system as though I had an internal regulator, when in fact my alternator was an early model which needed an external regulator. But all is good now and I have a working gauge.

 

[HenrysT]

Glad you got back to us to tell how you made out, some guys leave us hanging wondering what happened