Simple gauge wiring question

[iliketocrash]

I'm trying to wire up the lighting for my gauges to my dimmer switch in the car but there are four wires and i don't know which to tap into. Can anyone help?

[Nismo1182]

I tapped into the 2 wires (+ and -) going to the light in the ashtray.

[iliketocrash]

i wanted to wire it up so the dimmer switch would dim my gauges as well but i got too impatient to figure it out so i just hooked it into the dimmer switch plug at the 12v switched source. saved me a lot of wire and was really simple.