Just so ya know on our 17 Challenger 37TB the headlights are Projector, and are sealed units, meaning you have to replace the entire assembly, you cant replace just the bulb, or lens.
Our Low Beam Lens on the passengers side is broken ( discovered it when I was putting RainX on the headlights ). I emailed Thor for replacement info, and they directed me to Total Value RV. They quoted me a price of around $90 !
Just know if you have the Projector style Headlamps you have to replace the entire assembly.