Install the in line fuse in the trunk so it is an easy get to if needed.

Find a separate ground location , not a harness or existing ground location so the signal freq does not transfer to the system ground and screw up the radio, etc reception.

Is it a std light bar (7 to 9 light w/ direction/pattern control box) or just a dual light unit? I use a Superior Signals Traffic manager lite stick on my F 150 all the time and the controller and wiring are still in place. I keep the stick behind the seat and have used it in emergency and traffic assist situations using 4 in speaker magnets on the feet to stick it to the top of the cab.

yours is the rear deck install unit correct?