quick question about aftermarket back up camera's.
 

My girlfriends FX35's backup camera automatically turns on when the vehicle is placed in reverse,

my question is if i purchase a kenwood 8120 with a kenwood backup camera, does the camera automatically turn on when I put my car in reverse? Or is it a feature on the headunit that you have to turn on and off manually?

thanks!

i think it hooks up to the reverse lights or something so it does the same thing. Or you can also manually turn it on as well.

Correct! Most DVD units have a B.U. Camera input as well as the appropriate trigger which connects to the positive of the camera to switch it on when the reverse lights turn on (getting the trigger from the reverse lights is usually easiest to do because its close to where the camera is going.).

I do prefer a switch though in my car so I can flick it on while driving. Its personal preference though.

yes, ive installed allot of these. it is activated through the reverse wire and will trigger on your unit according to the settings

Everyone has it right. There is one wire (usually) that comes from the head unit labeled "Back-up Cam". This will go to the positive wire of one of your tail lights. That way, when you pop it into reverse it sends a signal to the head unit to put it in revere cam mode. When you put in in drive, the reverse light shut off and the signal is lost, telling the head unit to go back to normal mode. Most back up cam systems have a polarity setting, so even if you hook the wiring up backwards it will still work!

Reverse wire problem
 

Installed a Boyo VTL420 back up camera with a AVIC f-90BT Navi. in a 350z 2007 Roadster.
Found the Teal/Green wire(Reverse Wire) in the trunk of the car and tapped it
When car goes into reverse unable to see anything thru camera, unsure of what the problem is, im trying to eliminate some of the possibilities but getting stuck. Any ideas?

i have the 8120 and it turns on automatically.