We had a new RV several years ago (not a Thor MH) and one of the ceiling LED lights either stopped working or never worked. Factory had to order mine, so you may have to go through a dealer to get one from Thor.
When I got mine and began to change it I discovered it was wired backwards from the factory and didn't need changed. These LED lights lasts a long time. I would take it off along with a twin light and make sure the wiring is correct and still secure.
Full Time in 2017 Newmar Ventana 4369
pulling a 24' enclosed (Mini Cooper/Harley/Kayak)
(traded 2014 Thor Challenger)
US Army 70-73 Retired LEO