The Stovebolt Site Forums The Shop Area The Electrical Bay Gauge experts - need help testing my gauges

55.2 Gmc 12 volt with a small block

Trying to see if my temp and ampere gauge work or not. The ampere gauge has two poles. Temp gauge has one very unique pole. Here's a photo - https://flic.kr/p/uwde1B

Is there a way I can bench test them? I have a multi meter but I'm a rookie with it.

I do not know if the gauges were meant for a 12v or 6v system.

And I bought a voltmeter today that I plan on installing in place of the ampere gauge, but I would like to at least see if it works.

The AMP meter is best tested safely with a variable current source or supply and variable load to adjust circuit current.
If you have a fair understanding of electronics you can mock up a tester for this.
A multimeter by itself will only check the shunt resistance in ohms. You may show vary low current from the shunt but the meter coil may be open.

Your temperature gauge should be a heated bulb sender. It is not an electric sender.
From the shop manual -- The temperature indicator consist of an indicating unit in the instrument cluster, an ether filled bulb in the cylinder head and a small tube forming an air tight connection between the two units. As the water in the cylinder head warms up the ether expands causing then hand on the dash unit to move toward the right indicating the water temperature. --
Pressure on the fitting hole should show needle movement, but the unit will need a repair adding the bulb and tube.

OH, 12V system

Yeah, I'm probably not going to be able to test the amp meter, that's over my skill level.

As to the temp gauge, it's from a small block 350, not the original engine in the truck.

Temp still looks to be a bulb and tube mechanical unit, not and electrical type.

I had not done this for years but in past had a quick "dirty" check on the amp meter using a standard cheap 9v carbon battery (disposable). New out of package these provide about 5 amps of short circuit current. You apply the 9V terminals to the amp meter terminals direct for a second or two and should read about 1/6 - 1/4 of the scale for a 35amp meter. Then flip the battery and read the other direction.

Again a second or two at most to keep overheating the battery to minimal. The battery life will be sucked out of it so get cheapest battery you can find. No rechargeable battery types as short circuit is no good for them.

If you still have a radio shack go and buy model 270-324 catalog #2700324 Heavy-Duty 9V Snap Connector. for battery a HF 9V battery item#68383

Thanks 48X! I will try that at home.

I'm going to send all my gauges to Bob's Speedometer. He will test them for free and if repairs need to be made, I will go from there.