Back-up Lights not working

[frh3]

Purchased our 2001 31' Excella back in April. Doing some upgrades - Bargman Tail light black plastic fixtures were crumbling and lenses loose. Decided to replace with LEDs - fairly easy but now realize the Back-up lights are not working - probably never worked since we purchased (always check the running lights, turn signals and brakes but never put it in reverse to check Back-ups). Chasing down problem led to blown 15a fuse in TV engine compartment. Replaced, put TV in Reverse and fuse blew again - removed 7-pin connector, replaced fuse, put in reverse and fuse did not fail. Replacement lights not permanently installed, this happens with light wires unattached as well with neither CS or RS receiving power. Wiring diagram shows no fusing or breakers from 7-pin to tail lights - am I reading that right? How do I run down the short from here? Any ideas would be helpful.