I am getting an F code on the display. The switch is working and the basin is full. I have unplugged the unit, let it sit, and plugged it in again. Same issue.

SOURCE: the water refill icon keeps blinking, but the humidifier is full

have you checked the water sensor?

SOURCE: Kenmore 15408 Humidifier How to Reset CF

Per the owner's manual, you simply unplug your device for 30 seconds. Upon plugging it back in, the CF notification should be cleared.

This assumes you have also changed the filter, of course.

SOURCE: reset light on holmes product hls5000 humidifier

turn knob to reset....leave 15 minutes and then turn on

SOURCE: aprilaire humdiifier not working

Does your humidistat have any dip switches or a small jumper wire? if it does try switching positions of the jumper or change dip switch. hope this helps

SOURCE: Kenmore Humidifier not operating?

Turn the unit off, lift the fan assembly off the base, and push the connector together that goes to the float switch on the bottom of the fan motor. If you hold the switch in with your finger (careful not to get into the fan blades) and turn the unit on, the F indication should go away. F (as in Fill), apparently, means the base has no water. The plastic tube that sticks up out of the base floats on the water and pushes the switch. Put it back together, it should work!