Congratulations on the new TT -hope you get the problems sorted out soon- and welcome to the forum.
My trailer isn't here so I can't verify this, but as I recall there is a position for the fan on the thermostat labled 'On' and 'Auto'. Your trailer may be similar. Check the fan switch on the thermostat.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.