The internet/eBay is your friend here--there are many sources for simple changeout of the bulbs, just have to be sure the base is the correct one. I did all the lights on my old Suites and it made a dramatic difference in how long the batts stayed up for dry-camping. If you start buying at Camping World or some other retail source, it will get costly in a hurry, so check around and always take the old bulb with you to check the base.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired