[71GMC_3/4T]

Nichboy, you just ain't having luck with gauges, are you? Heh, I responded to your fuel gauge Q too.
What you need for the temp gauge to work is 12V on the + side of the gauge and a sender to ground (engine block) on the other. Maybe a wire for lights if you want them.
Have someone watch the gauge with the key on while you quickly scratch the wire to ground. The gauge should move. If it doesn't, you don't have the correct power to it, or it's defective. The reason I say to quickly scratch it to ground is that you shouldn't hurt it that way. I'm just not sure what the minimum resistance of your sender is. If you short it to ground for a long time, you may hurt it.