[Bob Putnam]

Ike,

There is a major difference between what an ammeter and a voltmeter does.

In an ammeter, all the car's current passes through the gage. That's why the wires are heavy.

A voltmeter only requires a tap to anywhere in the system and a ground. (that's where your second wire should be connected.)

By the way - I've changed my mind about the way the large wires are connected at the gage. While the setup would work, it will have the voltmeter "on" all the time, draining the battery if the car is kept dormant for significant periods.

The white and brown wires (#27) must be connected together somehow.

Or...

Alternately, you can run a new 10g wire from the circuit breaker on the firewall (after disconnecting #31 brown) to the 2nd fuse down on the passenger's side fusebox. Tape off the wires at the dash.

You'll also have to run a wire from the ACC terminal of the ignition switch to the voltmeter, and a ground to the other voltmeter terminal.