Roof vents and fans
Powered roof fans are a 12V motor, a switch, a lid that opens by crank or motor, and sometimes a rain sensor or thermostat. Most calls are power, the lid, or a leak at the flange.
The short version
- Fan dead: check its switch and 12V at the fan with it switched on. Many fans have a switch on the unit plus a fuse in the panel.
- Fan runs but the lid won't move: check the lid motor or crank gear, and any lid limit switch.
- Many fans won't run with the lid closed. That's a safety feature, not a fault.
- Some fans close on their own when a rain sensor gets wet or the thermostat is satisfied. Know the model's features first.
- Leak around a vent: inspect the sealant on the roof flange and look for a cracked lid or frame. Plastic gets brittle in the sun.
Shop tip
The model is on a label inside the screen. Features like rain sensors change how it's supposed to behave.
Try it on a service call
Put the lesson to work on a hands-on troubleshooting case.