With a moonroof, you can thread the wiring easily by pulling the plastic strip around the moonroof opening, and dropping the headliner enough to reach up there (after pulling the two plastic buttons that secure the back of the headliner where the light will go). Be sure to check back there to assure that your car has the metal frame that the light snaps into; some members have said their cars did not have the frame (although my late (2000) car did). Also remember to thread the wires UNDER the metal frame in the back, and then to the light; otherwise the wires will be in the wrong place when you try to snap in the light (once you look at it, you'll understand). Finally, the wires connect to the front dome light, which drops down by wiggling a small screwdriver into the space between the light and the larger housing (don't try to lower the whole thing). As others have said, the scariest part is taking the utility knife to the headliner...just push it up against the metal bracket, feel for where the opening is, and make a small cut first!