reverse camera setup

This is too basic to carry on but...2 wires + the signal lead on the camera yes? Black to ground and red? to 30 on the relay.

Ok I have a + wire from the switch to send 12 volts to the camera and the purple wire to the headunit. The purple wire and camera wire also see 12 volts when I put it in reverse. While I am in park or drive I want to be able to turn on the switch and get the same effect as if I had it in reverse. I ran the 12v from the switch to 86 and 87 and then the ground to 85. I ran the camera positive to 30 and the reverse light to 87a but that left no where for the purple wire to go on the relay. Thats the problem I am running into.

Join purple to 30. Yet again.

Ok I'll give that a try

Worked great. Sorry for the misunderstanding. Thanks again!