The REDARC Enhanced Lighting Controller enhances the brightness level of your REDARC gauge. When you don't have a dimming circuit to connect your gauge or it doesn't dim to your preference, the lighting controller allows you to choose both brightness and color. The GA-ELC is 24-volt capable and only one is necessary for a set of gauges. Once you've programmed your chosen dimness and color, the gauge will change based on nighttime and daytime settings. REDARC strongly recommends that an Enhanced Lighting Controller (GA-ELC) be purchased with all gauges. This ensures that the gauge is not too bright when driving at night, by dimming the gauge and/or changing the backlight color.. . . . .