Sometimes a crimp connection can be improperly done and eventually fail. The lights in the slide in our TT were flickering for quite a while. I almost ordered new lights and then checked the connections. Sure enough, a wire was barely hanging on because of bad workmanship.
I'd check all the connections at the fan, lights and switch. A voltmeter might come in handy.
Gil & Deb & Dougal the Springer Spaniel