The SWM 3 requires one coax and one control cable to operate the disk mech.
I would pull that plate and see what's there. Redwood installed the control cable and two coaxes, one for living room and one for bedroom from the Factory.
2018 Chevy 3500HD High Country Crew Cab DRW, D/A, 2016 Redwood 39MB, Dual AC, Fireplace, Sleep #Bed, Auto Sat Dish, Stack Washer/Dryer, Auto Level Sys, Disk Brakes, Onan Gen, 17.5" "H" tires, MORryde Pin & IS, Comfort Ride, Dual Awnings, Full Body Paint