It breaks the circuit when you turn the key off and the microamps needed to operate them is a minimal drain on the circuit that you use to trigger it.GW
I see how to wire a relay in but what exactly does it do, will it stop a parasitic drain when truck is off
I doubt that the draw is that much, so you could get away with just hooking the camera to your auxiliary power plug and not run a special circuit with relay. It will still turn on and off with the ignition switch, so no drain.