If you need to retrofit as OEM, there is lot need to happen. You will need wiring harness and light socket for the rear bumper, the steering wheel switch stick replaced with rear fog light switch trigger, proper wiring harness for the switch, possible replacement for light control ECU.

If just adding after market, then get the wiring and sockets for the bumper, ran the wires to the dash, find an empty switch location, get ACC or IG power, and relay for the lights.

 

 

It's doable. There is a member in GX forum did just for that. The concept is very much the same.

https://www.clublexus.com/forums/gx-...with-mods.html