Wiring Cathode to dome lights?

[Nexus1155]

they are actually going to send me the correct switch with return postage for the old one, thats cool because I was going to wire them on the weekend anyways which gives it time to get here.... I can find a power post, but what color is the door light one under the dash? is there also another place to wire the 12v wire, because i have really bad luck with ignition wires(blew out an ignition switch) Thanks alot!