Fantastic Fan Thermostat error

Took it apart. The on/off switch is keeping it from dropping down very far. I can see the contacts. Not sure what cleaning them will do since I know it works. The contacts is what I can hear click, it just seems to click too late - it is not that hot yet I have to set the temp almost all the way high for it to come on. It used to come on lower.
To do more I will have to disassemble from the roof. I may or may not do that.

MrWizard wrote:
If it's a simple mechanical thermostat it's just a bimetal strip with contacts, the temp adjust can set either the gap between contacts or the preload against the movement of the strip to close the contacts, I would start by removing the stat from fan and cleaning the contacts

I will try this before calling Dometic.

Side note - the fan has 3 speeds. Fast is power directly to the fan, while med and slow go through what looks like a heating element of two different sizes. I assume this "burns" off some power which then reduces the power to the fan and thus a slower speed. Conclusion, all 3 speeds use the same amount of power. Conclusion, it is better to use the high speed while the thermostat is on for maintaining temps while you are away (it will run less than a slower speed). Use the slow and medium speeds for comfort/noise level while inside.
or does fast use the least power?

If it's a simple mechanical thermostat it's just a bimetal strip with contacts, the temp adjust can set either the gap between contacts or the preload against the movement of the strip to close the contacts, I would start by removing the stat from fan and cleaning the contacts

Contact Dometic parts department. They own Fan-Tastic Vent now.

https://www.dometic.com/en/se/support/spare-parts

Let us know if you have success getting the part you need.

Just slightly off topic but would you, could you, replace the t/s with an on/off switch?