So my rear window defogger doesn't work anymore, so I'm thinking about using the switch to power a pair of led lights I have mounted on the roof rack. Has anyone ever done this or know how it can be done? Thanks!

 

Defrost switches usually have a timer.
Inspect hatch wiring between hatch and chassis, it is known problem area.

 

i did this on mine and works a treat, i run a single halogen spotlight for my reverse light, if it is on a timer it must be quite along time as it has never turned itself off, the circuit is fused and got a relay in it so all good.