Hmm... Have you had this trailer very long? Has it always had this problem or ??
Since the battery has power and fuses seem OK, I'd check the battery ground next. There have been a few posts indicating that can be a problem.
Sherm & Terry w/rescue Eydie (min Schnauzer) & Charley (std Poodle)
SOLD:2015 Jay Flight 27RLS, GY Endurance (E), Days: 102 '15, 90 '16, 80 '17, 161 '18, 365+ '20
SOLD: 2006 Ford F350 PSD, 4WD, CC, LB, SRW, Camper pkg., 375,000mi
Full timing: Some will think you're crazy, some will be envious, just enjoy the freedom!