you have to run a few wires, pretty much its the same as , say a car stereo. you can use the original dome light wiring for a constant 12v, and the door pin wire there for the dome lights, and the sheet metal base for a grounding point. But you still need to run the temp sensor wires, the ignition wires, and illumination "dimmer" wire. i built a separate wiring harness for this, that i spliced into the original connectors (i was sure to keep boths sides of the plugs when i removed it from the donor vehicle, with enough wire for good splices.) I soldiered all "permanent" connections in the harness i constructed.

hope that helps...