Tired Bill: no, sorry, i also could not find a fuse specifically labeled for rear lights. in the end it was not a fuse problem - instead was the more common water infiltration problem combined with the pins on the light bulb receptacle being a little loose. solved by "squeezing" pins closer together for better contact, and reinstalling light lenses with Butyl tape for water protection. Hope that helps. I eventually will replace the entire light housing as the leaks will return. See many other threads here about better light fixtures.
2015 Thor Axis 24.1 (2014 Ford E-350)
Safe-T-Plus, front SUMO's, Roadmaster rear sway bar, TST TPMS
Toad: 2020 Ford Escape Hybrid, Blue Ox Alpha