Originally Posted by htjunkie
I have 1 clear driving light hooked into my back-up lights. I want to add 2 more of the same lights on top of my toolbox. Question is..can i wire these lights to work with the back-up lights as well as with a separate switch?
Yes using a simple automotive 12v SPDT relay (at any auto parts for about 4.00 dollars), a diode (1N4002 or 1N4004 for .79 cents at radio shack), some 14ga and 12ga wire, and a 12v SPST (lighted or unlighted) switch of your choice. Make sure you add a 1-5 amp fuse to feed the dash switch and a fuse (not to exceed 20 amp) feeding the power to the relay.
The lights will come on when you put it in reverse or when you flip the switch on.
I would recommend switching the current clear lamp you have connected into your backup lights to feed from the same relay. Sooner or later its may overload your backup light circuit and either blow the fuse or worse.