How do I access the X5's reverse light circuit and ground wire?

[bagpype]

Originally Posted by crystalworks

They run in the lift gate so you'll have to trace them where they enter the truck and make their way to the light control module or grab them inside the lift gate. Left side reverse light + = white/yellow and Right side reverse light + = blue/yellow.

Forgive me for my ignorance but I’m not finding said wires. Are we talking inside the truck under the headliner or under the plastic covering on the lift gate itself?