Thread: wiring power roof vent?

Im replacing a power roof vent. The vent has just a black and white white wire. The existing vent (removed by someone else) was hooked into a box that had a black, white, and red wire. What do I do with the red wire.? There is a switch in the house that will shut power off to this box. I hooked black to black, white to white, fan works fine, but switch does not work.

With a tester of some sort, does the red wire become live when the switch is flipped? Most power vents have a thermostat that turns them on and off automatically.

Hook the black of the fan to the red wire in the box and try that.