There should be two screws (#2 Roberts) well hidden in the carpet on the top of that box. Typically, the carpet acts as a hinge on the most forward part of the top. Use your fingers and separate the fibers on the carpet and you'll find the screws. It's NOT nailed down, but frustrating to find the fasteners...
As for the light strip, I'd use double sided foam tape.
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
|