voltmeter light

Been messing with this for awhile now, thought I'd see if anyone here could talk me though this. In a nut shell, when I connect the gauge cluster lights, my volt meter drops to zero. All of the lights work except for the volt light. When I dissconnect power from the gauge cluster lights, everything goes back to normal. This is a gauge cluster for an M38-A1, Buick 231 12volt system. Do you think it could be the actual bulb in the voltmeter? It still looks good but I don't understand why the bulb has 2 leads to it. One is the power I hook to it, the other connected to the right side of the guage. Now that it's getting dark early, I figured that it was prolly time to get some of the lights working in this sucker. Here is a picture.

Dondo

http://members.cox.net/mtbiker70/Jeep/DSC02216.JPG

 

Yeah, me too. Hence the questions..
Do the gauges need to be grounded at all? What are the typical connections for an aftermarket voltmeter w/light?

Dondo

 

Is that bulb maybe for an indicator light, and not for illuminating the guage?

 

sometimes there is power at both terminals what this does is turn off the light if the system is good on both ends and if one goes to ground the light comes on because all your voltage is going to ground and the voltage is no longer equal on both sides of the bulb so it turns on.

 

That GND in the picture goes to the vehical ground, so at least the voltmeter is grounded. I guess. I dunno.

 

The light socket has to be grounded, thats why there is two wires. It looks to me like you have power going in both wires, and when that happens the voltages is equal on each side and no current will flow which causes all the lights to go out.

 

So, I should take my green ground wire and connect it to one of the leads on the bulb? What are the two connections on the bottom for? I figure one is power, but what is the other? The way it is now, it is connected to the other lead on the bulb. Does anyone know, are those 2 big thumb screw things on each side just to hold the gauge in? I suppose I could check that easy enough....huh?



Dondo

 

Most volt gauges hook up this way: dash light power to one side of illumination lamp, other side of lamp to ground. Ignition 12V (12V that's only on when the ignition is turned on) to the correct terminal of the meter. Probably labeled "S" (for "sender") or "+" (for +12V). Other terminal, hopefully labeled "gnd" or "-" goes to ground.

The thumb screw things are basically just there to secure the gauge to the dash. On a mil dash like that I like to run an actual ground lead from a common point in the gauge area somewhere to a good ground in the engine compartment and then tie all the gauge grounds to that common point. Helps ensure it all works right and also lets you run and test the gauge panel while it's out of the dash.

Stan

 

It looks like there are two spade terminals on the meter which one should be connected to a hot lead from the ignition and the other to ground. No wires should be connected to the mounting screws.

 

I see 3 grounds in the photo.
as Stan mentions, only 2 needed.
one for lamp, one for gauge.
you might not be getting good ground through the brackets to the panel.
also, if testing with the panel out, your ground may not be as good as you think.
with panel out, have you tried touching another ground wire to the panel ?

 

Thanks. This is exactly what I needed to know. I get a little nervous playing with the birds nest of wiring on the Jeep. I'm constantly afraid that I'm going to leave something open, or something grounded that shouldn't be, etc and end up burning the entire thing up.

Dondo

 

I hooked one wire on mine to the light switch, the other I ran to the ground stud on the dash. would try another light bulb as well.

 

I've put a diagram up on my site that might help. Go to:

http://home.comcast.net/~sday77/m715/index.htm

Follow the repair info link to the electrical page and click the diagram.

Stan

 

ahhhhh....yeesssssssss....

Nothing quite like finding a lose ground wire to make everything work great in your old Jeep......

My ground wire, which I "thought" was good, wasn't. Now it is and all is right with the world....

This is the first time since I bought this Jeep, 18 months ago, that everything that is on it, electric wise, is working.

Ground.....gotta remember that....check the ground....

Dondo