Ammeter to voltmeter conversion?

[Number21]

My '73 came stock with an ammeter, instead of a voltage meter like later models. It has been long since unhooked. I would much rather have a voltmeter. Can I get a stock voltmeter and replace the ammeter? If so what year(s) would work in my '73?

[terryj]

An ampmeter operates different than a voltmeter, if your going to use the original circuit then you'll have to find out what circuits were also being fed by the ampmeter. An ampmeter is a flow through device, voltage enters one side and exits the other and the meter reads that amps. A voltmeter is not a flow through, voltage enters the positive side and goes to ground on the negative side, operates like a standard voltmeter.
Most amp meters were used to measure the charging current of the alternator so your ampmeter would be "in series" with the charge line for the battery.
I'm not sure on the 73 is they were the plug in gages, it would seem that an ampmeter may have the mounting nuts for the terminals due to the current. Like I said, I'm not sure on this.
Your voltmeter can be installed using any 12+ switched supply and gound out the negative side of the meter.

[willett]

Do not hook a voltmeter up where the ammeter was. You'll start a fire!!
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[Jonboy]

My '74 originally had an ammeter, but it's long gone. It's a pretty easy conversion to do. This was done when I got the truck, but I switched it over to another cluster. Take the cluster out, and pull the Ammeter out. remove the clips that hold the gauge to the carrier and make contact with the printed circuit. You will hook up power and ground to the voltmeter going in. (use a ring terminal and bolt it to the back of the gauge post, I am pretty sure it is a 10-24 nut). Like I said, I used the clock wiring from the fusebox (moved to a switched power terminal) and ran a ground wire from the ground block on the left side of the cowl. I put the wires through the holes in the back of the cluster. Easy Peasy.

[bsccp]

Originally Posted by bsccp

Ok, I'm planning on bringing back to life a 74 k10. Have a 99 Tahoe 5.7 vortex with 4l60e and np241 (89-91 Sub) for drivetrain.
I know that the 89-91 Suburban electronic speedometer will work with the ecm/vss but has anyone converted the ammeter to voltmeter?
Any suggestions or experience?

Found the correct thread😮

Originally Posted by Jonboy

My '74 originally had an ammeter, but it's long gone. It's a pretty easy conversion to do. This was done when I got the truck, but I switched it over to another cluster. Take the cluster out, and pull the Ammeter out. remove the clips that hold the gauge to the carrier and make contact with the printed circuit. You will hook up power and ground to the voltmeter going in. (use a ring terminal and bolt it to the back of the gauge post, I am pretty sure it is a 10-24 nut). Like I said, I used the clock wiring from the fusebox (moved to a switched power terminal) and ran a ground wire from the ground block on the left side of the cowl. I put the wires through the holes in the back of the cluster. Easy Peasy.

[hatzie]

This is a pretty old thread...

Fires usually get started by folks installing the Ammeter clusters in the 1976 and later trucks... usually the tach clusters but the tach isn't the piece that causes the fire.
The Ammeter in 67-75 GM trucks is not a high current direct read unit like the old 1960's & 1970's Chrysler units it's in a shunt.
In the 73-75 trucks the ammeter measures the voltage drop between the termination points of the shunt at the starter BAT lug and the Firewall Stud J-Block. Both termination points have an AGC fuse holder.

You can use the Black/White wire from the J-Block for + feed to your VOLT gauge but you'll need to add a ground and remove the fuse from the Black wire on the starter.

The 76 & later gauge clusters use a different pinout on the cluster plug. The capillary tube oil pressure gauge 1976 and early 1977 will be the easiest clusters to swap into the 73-75 trucks. Late 1977 - 1980 will require an additional wire for the oil pressure sender.

This is the post in the FAQ with some pretty decent cluster pinout tables. http://67-72chevytrucks.com/vboard/showpost.php?p=4595551&postcount=2