I know its probably already on here but I can;t seen to find it. I have a 2007 RAM 1500 sxt 4X4. What I'm trying to do is hook up two fog lights on the rear bumper and hook them up to the light on top of the rear of the cab. Using the factory (bed light) switch already on the dash.

 

Fairly easy install. Basically when you want to install a set of lights and use an existing switch you should run power to the new lights and put them on their own relay, fused appropriately and the only difference would be to run a wire to where you would normally run a switch wire to the relay of an existing light on the switch you want to use. You can also just tap into the wire coming off the switch to the existing light's relay.
In this manner you are running your aux lights completely isolated and on their own power but simply jumping about .3A off of the existing source...

 

Thanks HammerZ21,

You woul'nt happen to know what color wire i should tap into at the dash switch to activate the relay for the new lights?

 

Not off the top of my head, I've tapped into the high beam relay, fog light relay & running light relays, and reverse light wire but not the one you are talking about...