I would call Dometic Customer Service and see if you can buy the part, or direct you to a service place close by. (There are more than just dealerships)
I found out a radiator repair place around the corner was a certified Dometic repair location and they ordered a part I needed under warranty and let me install it myself.
Lou, Laura, & Freya the wonder dog
2008 GMC Sierra 3000HD Crewcab SB Allison Duramax
2019 Flagstaff 8529FLS - Pullrite 3300
HAM CALLSIGN - KC3FFW