2017 3820FK Furnace won’t turn on

[Sohlsken]

It worked fine last night but today, it won’t even turn on the fans. I set the controller to auto, turned it up to 90F (it’s 64F in here) for good measure, and nothing happened. The AC works. I can turn on the fan settings individually.

I have pulled the fuse and am going to go for a walk to give it ample time to reset. If that doesn’t work, what do I try next?

It’s not an issue of it not lighting. Nothing at all happens.

Thanks in advance.

[Daryles]

So you are saying the thermostat has power (lights etc), but won't even turn on the fans?
Does the bedroom thermostat work?
If so and they are the same, maybe swap thermostats?
Take pictures of the wiring before you swap them.

[jsb5717]

Can you pull the exterior furnace cover and look at the main board to see if there are any lights on it and also check the switch to see if it's off. If your furnace fuse is a resettable one the replace it with a standard fuse.

If the furnace has power and the switch is on then it should respond to the thermostat. At the very least, the fan should kick on. If not, do as Daryl suggests to see if it's the thermostat. If that doesn't work then I'd suspect the main board.

[Our3231CK]

We also have a 2017 3820FK, our furnace had similar issues in fall of 2018 in Sedona AZ, after numerous tests we ended up with a mobile repair tech because i couldn't find the main board online to buy. Tech replaced it with our extended warranty and we haven't had any issues since.
We camp and travel in various environments, the tech advised i routinely use low pressure air and blow out sand and dust, which i have been doing twice a year.