I had an Car that had a reverse camera that was triggered when the reverse lights came on. I thought the camera would have been tied into the transmission nuetral safety switch, but it wasn't, only the reverse light. So I tapped into the control wire, mounted a switch under the dash, a diode, and viola!, any time, any where, any gear or speed, I just hit the switch and the reverse camera came one. Pretty trippy watching it as you are moving forward as fast speed. But it worked! I could sit in park, hit the switch, and watch everything going on behind me. Stealth!