I have an AppRadio2. When I first hooked it up, I wired the camera power to the accessory red wire off my vehicle harness, and used a PAC RP5-GM31 harness. So I wired the purple with white stripe wire off the radio into the purple with white stripe wire off the PAC harness.

Then when I drove, the camera would randomly come on at all times. So I took the radio out, installed the latest radio firmware update, and then disconnected the purple and white line off the harness, and ran the purple and white line directly to the backup lamp fuse on the circuit breaker.

Put the radio back in, now the camera works when I put the vehicle in reverse, and turns off in park. And it was good for one day. And I have the ability to push the camera icon to get the camera when the vehicle is not in reverse, which is nice for watching my boat while I tow.

But AGAIN the problem has come back where the reverse cam constantly comes on while driving.

To sum things up:

The purple and white stripe wire goes into the reverse light fuse.
The camera is powered off the accessory line from the back of the radio.

the only final thing I can think of is to disconnect the constant power source off accessory and wire it to
the purple and white line so it only works in reverse, which means I will probably lose the ability to use the camera while not in reverse, but that is better than constantly randomly coming on. Am I doing something wrong?

bump. very frustrating.

Is your camera button at the app radio blue or grey?

blue when I leave the polarity on ground or battery, grey when i leave it to "off"

turn polarity to battery or ground, then on main screen just hit the blue camera and leave it grey. then shift reverse to check if camera works. the blue camera button is supposed to turn on the camera whenever you would like(in case you wired this way), so you want to leave it grey, this way whenever the radio sees the reverse signal it will switch automatically to the camera. 

I found this problem happened to me briefly so far. I could not get into the menu to adjust settings even after a reset. Put your car in reverse and if the screen comes back, change your options, mine was Mirror (no GND). Hope this helps/

I have the original problem described in this note. I have the Violet/white (REVERSE GEAR SIGNAL INPUT) connected to the reverse lights and menu setting for the camera is battery.  I'm not sure but it seems like this happens more when the lights are on. Could the rear lights be causing some current to make the radio think the reverse lights are on?

When I first installed the camera in my VW, I wired the camera directly to the reverse lights And grounded the to the chassis. The picture had "noise" lots of lines and sometimes it would not turn on. So I checked and noticed the reverse lights didn't turn on with 12v... It had about 8~9v. The solution to my problem was to add a relay, with the reverse lights as trigger and the output from the relay would throw a full 12v.

The wire behind the head unit is there only to change to the camera screen. Make sure your camera has a solid 12v source and you ground the camera to the chassis or a solid/clean ground.

Also, I was reading on the manual from my camera and it said if you leave the camera on for too long, it would show "rain" or artifacts. For this reason my camera only turns on when reverse lights are on.

If I press the camera button and leave it blue while the car is on drive or park, all I get is a intermittent black screen that comes on and off randomly. So that's why I leave it grey.

I also installed my cameras with a wireless transmitter for reverse cameras that I bought on eBay for $19. This way I didn't have to run the composite wire all the way back making my installation super easy.