The interior LED lights pull away from the ceiling. Use your fingers around the perimeter of the lens and gently pry it away.
Are you sure the outside radio doesn't work? I had to turn my volume up pretty high before I started hearing it on the outside speakers. I also use the 3.5mm plug and use my iPod.
2013 Palomino Columbus 320RS
2007 Dodge RAM 2500 6.7 Cummins
Reese 15K manual slider
M.I.L. in Florida for good!!