Homelink upgrade on Prius III

I bought my Prius III on Sunday. I took the Gentex homelink mirror with auto-dimming and compass off my Honda Civic Hybrid (traded in). I have the homelink wired (just tapped into the passenger visor light wire that runs inside the headliner when you remove the light/sunroof switch unit). that took care of the homelink. What I need it to find the gray wire to tap into in the wiring harness to the light/sunroof switch unit (hot with ignition) so I can get the compass and auto-dim feature working. The PDF is way overboard on the number of steps.

Thanks!

 

I ended up buying my GenK41a from BrandNewAuto. My local speed-shop installed it in under an hour. They tied it into the panel where they had access to everything.

 

Did you ever find the wire to the sunroof that is hot only when the car is on? I'm looking for it as I type. It also shows the ground wire being taped to another wire, but my harness has the ground screw down round end. I saw what looked like two threaded screw holes in the metal I think in the compartment in front of the light sunroof switch unit. Is this where you grounded your wire?