I believe there is a pop-up switch that turns the fan ON when the lid is open.
I had to bump the fan/ceiling to make the switch work. You would have to get up on the roof and the cover OPEN to lube the switch.
Siggy & Ursula.
2011 Newmar DSDP 4020 (no Tag, no DEF, 07 emission),
FTL XCR ,ISL 400,2015 Jeep Cherokee Limited, 4x4, V6, Active Drive II, BrakeBuddy