Check in the cupboard your switches, tank level monitor etc. are mounted on. It may be in the upper cabinet to the right of the TV and above the coat hooks. If it's there, you will see box made from wooden paneling on the back wall of the cabinet that removes and the relay board is in there.
In my unit it is above the kitchen sink right inside the door. The relay cabinet is inside the cupboard on the wall behind a cover. I had to get at mine while trouble shooting the slide motor.
Not the same unit but hope that helps.
2016 Jayflight 26BHS Elite
2014 F150 4x4 Super Crew, Eco-Boost, Max Tow
Bayliner Trophy 2002ff