I'm guessing the fans. Could be either, but the fans are the more complicated. You can check the switches w/a volt meter at the out put side. The side w/voltage always is input, the other is output; there may be two sets of contacts- one for light in the switch plus the fan operating contacts. If voltage is still present on the output side after the fan(s) quit then its the fan circuit or the fans.
If these are the "Overhead Fans," they run thru the Vansco multiplexer (VMM) under the plastic skirt in ahead of the passenger's feet and under the dash. Input LEDs 13 & 14 are Hi and Lo and Output LED 9 goes to the fans. You can remove the plastic skirt panel (iirc its velcro'd on only on a 2006, or there may be a coupla screws on the left side also) and check these LEDs. If the input or output goes out when the fans die, it might be the VMM circuit.
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project