Identifying Reverse Wire - Navigation

[rwooley]

Hello all,
I'm trying to solve two problems at once, and doing so requires me to identify the reverse gear wire that tells the retractable screen to emerge from the dash. I'm about to replace the factory head unit with a Legend aftermarket system. I'm also putting in a more modern (higher res) backup camera to go with my nice new large screen. My goals are 1. Disable the feeble retractable in dash screen that takes forever to emerge (I don't need it anymore) and 2. Tell my new head unit when I'm in reverse so it knows to privilege the rear camera input. I know all about wiring this to rear backup light circuit, but I'd prefer not to do this as I may sometimes want to call up the rear camera input without being in reverse (perhaps I'm sitting in a parking lot and want to see what is going on behind me). So, ideally, I'd power the camera from a local accessory power, which turns it on when keys are engaged, and I'd cut and use the reverse wire going to the current nav unit to tell the new unit when I'm in reverse while simultaneously disabling the old nav from coming out.

Thanks for any help.

[Krons]

For anyone coming across this thread, was light blue one on my 08 S60. Just put backup camera on.