Need Help Wiring VDO Temperature Gauge
 

No instructions in the box and on line cannot find this particular gauge. Three places to wire on the back marked G-S-I. Assume G is electrical ground but don’t want to burn the gauge out. Help appreciated!
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I believe it would be Ground, Signal is the wire from the temp sensor and the I is probably for light (illumination?)

From the googles:

On the back of a VDO gauge, G, S, and I are the wiring terminal designations for Ground, Signal, and Ignition (power). These labels are essential for properly connecting the gauge to the vehicle's electrical system.

Here is a breakdown of each terminal:
G (Ground): This terminal must be connected to a reliable ground point, such as the vehicle chassis or the negative terminal of the battery. A poor ground connection is a common cause of erratic or inaccurate gauge readings.

S (Signal): This terminal is for the signal wire, which runs from the sending unit (sensor) to the gauge. The sending unit measures the parameter, such as temperature or oil pressure, and sends a corresponding signal to the gauge.

I (Ignition): This terminal is for the 12-volt (or 24-volt, depending on the system) ignition-switched power. It ensures the gauge is only powered on when the vehicle's ignition is turned on.

One thing that's important with CHT gauges is the type of wire and connectors you use. Apparently the voltages produced by the thermocouple are quite low, and even using the wrong type of wiring can lead to inaccurate gauge readings. If you do a search on the topic you'll see what I mean.