Our '17 Axis 25.5 has 3 vent fans; one in rear bathroom, one amid-ship and one forward near kitchen. All 3 exhaust only. However, being that they run on 12 VDC, it wouldn't be difficult to rig either a switch with a reverse position or to rig a small separate switch that would reverse the power leads. Most DC motors will rotate in the opposite direction if power leads are reversed. Of course, if you rigged a separate switch to reverse the power leads, the main factory fan switch would have to be in the off position when you turned on the reversing switch.