Thanks for reaching out, Kim!
It sounds like you're needing the Replacement 17-rpm Lift Motor for Dometic FanTastic B Series Roof Vents w/Powered Lifts which comes in White # FVK6010-81 and Off-White # FVK6010-80 colors.
If your lift motor looks different then please feel free to send in some photos so I can see if we have something that will work! view full answer...