Connect the blue wire to the red wire.
Can you wire a ceiling fan to a dimmer switch.
The new switch does require an additional electrical wire.
If you replace with a blank plate wire nut the black from supply to this black and again cap the red.
Connect black fan wire to the black ceiling wire.
Your power supply line the black wire should be feeding both switches and those switches power the fan black or the light blue.
A broken ceiling fan motor and a house fire are obviously not ideal outcomes however there is some good news.
To do this method the wire from your wall circuit to your light has to have 3 wires.
If it s more than just a dimmer you might keep it in a box for if you can use it later.
By all means you can connect a ceiling fan directly to a dimmer switch but you may run into problems along the way.
If you replace with a plain switch switch the black wire up to the fan and cap off the red wire on both ends.
If you locate this switch then both ceiling fans can be wired from one switch.
A dimmer switch for the lights will be available in several watt sizes.
With a situation such as this it would be best to have a separate 3 wire cable from each ceiling fan to the switch box just in case the desired method of control will be changed.
These typically require you to leave the white neutral wires in the switch box undisturbed and connect.