I just finished installing an interior roll bar light in my YJ. I used wire ties to fasten it to my rollbar cover. I used one of the cheap lights off ebay that use a standard bulb with one wire to the center and a cheap push on push off type switch. The tip I have is by running three wires you can have the interior roll bar light work when the door(S) with switchs are opened or when the roll bar switch is turned on the roll bar light will illuminate AND the underdash lights come on. It is real easy. What I did was install the switch so it interupts the ground wire instead of the hot wire. This ground wire from the switch goes straight to the frame and is grounded under a screw. OK now I ran a ground wire from my underdash lights ground wire to the new roll bar light bypassing the switch on the roll bar light. while I was under the dash I also used the underdash lights
- wire to supply power to the new rollbar light eliminating the additional work of installing a fuse. Now when the doors are opened the overhead light and underdash lights come on. When someone turns on the overhead light by using the switch mounted on the roll bar light, the ground backfeeds to the underdash lights and they come on at the same time as the new roll bar light. Pretty cool huh. Offgridman