On a Dometic Fan-Tastic Vent 3350, the three-speed fan, reversible airflow, thermostat, rain sensor and powered dome lid use separate switches and circuits. Dometic's original 2014-and-newer wiring schematic identifies these components so you can compare the failed part with the correct replacement.
Original 3350 wiring schematic (2014-current)
The original Fan-Tastic Vent drawing shows the 12-volt supply and 4-amp fuse, three-speed control, airflow reverse switch, dome-position switch, 17 RPM lid-lift motor, rain sensor, thermostat and electronic control board. It also identifies the 9050-90 A board and terminal positions.
On a phone, open the PDF separately to enlarge the wire colours, labels and terminal positions.
Understanding the numbered wiring key
Use these groupings to locate a circuit on the factory illustration. The original PDF provides the full wire-level part numbers and connections; use that document for exact wiring verification.
| Callouts | Wire identification | Component circuit |
|---|---|---|
| 1a / 1b | Black 16 AWG | 12V positive through the 4A fuse to speed control |
| 1c / 1d | Black and red 16 AWG | Reversing switch to ventilation fan motor |
| 1e | Yellow 16 AWG | Fan speed control to control-board positive connection |
| 2a–2d | White 16 AWG | Ground path through board, thermostat, reversing switch and lid switch |
| 3a / 3b | Red and striped black 18 AWG | Control-board outputs to 17 RPM powered dome lift |
| 4a / 4b | Orange 24 AWG | Board connection to dome UP/DOWN switch |
Replacement switch, lift motor and fuse components
These are individual NewRVParts listings in the Fan-Tastic service family. Check the exact component, original label and model revision before selecting a replacement; a similar-looking switch or motor is not proof of electrical interchangeability.
Identify the model and the failed circuit
Check the complete vent model label, existing control-board number, lift-motor RPM rating and the switch body before ordering. The 3350 schematic includes reversible airflow; Dometic's related 3300 schematic has a different fan-direction switching arrangement, even though both use a 17 RPM lift motor and thermostat/rain-sensor system.
For the numbered roof-lid, screen, garnish and lift-arm service diagram, see the Fan-Tastic Vent replacement parts guide. This 3350 wiring page does not establish parts compatibility with 7350, 8000 or other Fan-Tastic models.
To compare the 3350 with the manual-lift 1250 or wireless 7350, see the Fan-Tastic Vent model and parts diagram index.