I put one on my Jeep Grand Cherokee for two reasons- to give me a step for removing the NMO antenna before going through the car wash, and give me a mounting point for some aux lighting that doesn't diminish the departure angle of the vehicle.
I started with the stock Smittybilt Beaver Step and mounted the lights to it, then stuffed a relay into a 7-pin RV plug so the whole thing is powered and triggered through the plug on the jeep- so no cut or tapped wires.
The relay is tripped by the reverse pin in the RV plug, which allows power from the aux power pin to power the lights.
It's also completely modular- I can use it on my other vehicle that has a standard 7-pin RV outlet. Just pull the plug, pull the hitch pin, and move it to the other vehicle.