Digital Voltmeter Wiring
 

I ran across a digital voltmeter in a old tool box. I don't remember where it came from. I put the red and black wires across a battery, and it works! Even flashes on and off under 12V. So I think im going to install it in my car.Here's my question. There is also a purple wire on it. What could that be for?

Re: Digital Voltmeter Wiring
 

It’s likely lighting.

Re: Digital Voltmeter Wiring
 

It IS lighting. But not backlighting since it is digital. So when there is no power on the purple wire, the display is bright . When power is on the purple wire,the display dims.
My car has no master cut off switch and I normally do not disconnect the battery, the gauge will display forever, so I hope the parasitic draw is tiny.

Re: Digital Voltmeter Wiring
 

If you have msd ignition, they live a lot longer if you disconnect the battery at night and after you leave the track.

Re: Digital Voltmeter Wiring
 

Its Big stuff 3 and coil packs.

Re: Digital Voltmeter Wiring
 

Everett, the purple is to dim it, if I’m remembering the ones I had before, correctly. I just capped them, with a crimp end.

Re: Digital Voltmeter Wiring
 

Kenny..now I remember where that gauge came from..It was in that center console in the Cutlass!..along with 16 miles of wiring LOL. I found a new home for it.

Re: Digital Voltmeter Wiring
 

the purple wire is an option to dim the display when the lights are on. You can connect the purple wire to a tail light or park light on wire.

Re: Digital Voltmeter Wiring
 

Huh?????
Dan