How do I access the brake lights on 2010 CL550

I checked it and the lights are out, I need to know how to access the bulbs.I called the Stealership and they informed me the lights are a led strip and I would have to purchase the bulb harness(land support)
I know I have to access the panel thru the truck, but I don't know how and the Stealership is charging $140 to change the the bulb harness 1 hour is minimum the charge for all labor, I need to know is this minor job or should consider letting the do this:confused






