On my 2013 F250 hitch receiver, the ends (left and right) are open. I used some hollow 2" square tube stock, built two extensions, plugged them into the ends of the receiver and plugged the lights into the bumper 7 pin connector. We almost always use the "in bed 7 pin connector" with the fifth wheel, so I just got in the habit of leaving on the truck. I used square U bolts to wrap around the extension and the end of the receiver (sort of like an anti-rattle clamp) to hold them in place. When I traded the truck, I forgot to take them off and just haven't gotten around to building another set... Square tubing is in the pole barn, I just need to cut a couple of 8" lengths and drill holes for the LED lights that are also sitting on my workbench, again, in the pole barn....
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS