When parked in FL for the "Winter", I use an old ATT phone plug in transformer ( 120 AC to about 12 VDC ) and connect it to a 3", 24VDC muffin fan from a computer. This way the fan runs relatively slow with very low noise and keeps the electronic gadgets from overheating.
Things like that, I find in my collections in the garage or the flee market.
Siggy & Ursula.
2011 Newmar DSDP 4020 , (No DEF, 07 emission),
FTL XCR Chassis , Cummins ISL 400 HP