Reverse light wire 2011 Sierra

[constantmotion]

I have a 2011 Sierra and I'm hooking up an external monitor for an aftermarket backup camera. I am wanting to tap into the reverse light wire to power on my monitor. I plan on tapping into the reverse wire at the trailer plug for the camera. I haven't been able to find out exactly which wire to tap into. Seeing olive, light blue, green, and dark blue listed everywhere and referencing to plug on the far right. I guess I really don't know where the BCM is. I see a box that is positioned vertically under the dash with about 7 different colored plugs in it. I have attached a picture of it. The wire on the trailer harness is labeled Lt Green. Can anyone help me out?

 

[wottenad]

This is the Left I/P Junction block, and it's located between your foot brake and e-brake on the firewall under the black square cover.

 

The reverse wire is the dark blue wire in the top right pin (pin 8) in the light gray plug in the top right port (X10):

 

 

[constantmotion]

Are you sure about that? I put my voltmeter on that wire and get 8V with reverse light on or off.

[Zebrafive]

Terminal 8 in X10 is the relay trigger for the backup lights relay. This comes from the BCM.

Terminal 5 in X11 is also the same wire.

 

I am not sure why you are seeing voltage with no backup lights request.