I have installed a aftermarket gauge disc set, and I need to find the right source of power. As it is now, it is always on when my car is running. I do not remember which fuse I am currently using, but I think the name is "gauge". I have tried a lot of fuses, but none of them fits my desire.

I want it to light up when the other lights light up. (Heater controls, etc.). What kind of fuse should I use?

Aftermarket gauge disc set? Cluster gauge? Or am I way off?

Correct.. Sorry if I was unprecise.

lemme hook you up, this is what i used as a reference install
Your pretty much running them into the "illumination" circuit. So when you turn on your lights your aftermarket set should light up

Hmm, there is no circuit called "illumination". I have tryed the "gauge" and "panel" circuits, but they are not working as I want it..

Somebody knows?

That link I threw up there pretty much is a shot off of the panel lights. So when you turn on the panel lights, the aftermarket gauge set lights up as well. Unless you happen to have some sort of switch that came with the gauge set that can not be left in the "on" postition all the time. I have the same problem as far as the switch goes. You can try to bypass it or just flip it when you want the face lit up.