Originally Posted by javelin
Do you have the RV Custom BCC box in your unit (black box, driver side, engine bay)? If yes it might be fuse F15 on connector P5 inside the BCC. Be careful opening and working inside this BCC......access can be a giant PIA.
The 2014 Ford F53 manual for my prior 2015 Challenger has F15 of the BCC as a 20 amp fuse for Trailer Tow Park Lights. There is no fuse in the BCC for the electric mirrors.
Since the mirrors are a Thor installation and not a Ford install it makes sense that the fuse would be in the passenger's compartment fuse box located by the driver's left foot. I could be wrong but that is my thought based on the manuals I still have. If it were me I'd get the Ford F53 manual and start looking for fuses installed in location marked "Not Used".