Mercedes ML550 brake controller questions

[Ken D]

Last month bought 2012 Mercedes ML550 with factory installed hitch receiver. We have 2017 Flying Cloud 26 RB with ProPride WD hitch that we want to tow with the ML550. Current TV is 2013 Silverado 1500 with Prodigy brake controller.

I have the spec from Andy at Can-Am RV for hitch re-inforcement for WD hitch.

My local RV shop has lots of experience with brake controllers but has no experience with working on MB. They asked I do the following research.

Lookng for comments about effort required to install Prodgy brake controller:
1. where did MB locate the end of cable wiring from the hitch that I need to connect to brake controller?

2. does the knee airbag under the steering column extend to under the ignition switch such that I can not safely put the brake controller on the console above my right knee?

thanks
Ken