This is potentially dangerous and you would need to buy a special dimmer switch and a fan speed control. Before you switch off the power have the ceiling fan set at the highest level.

Ceiling Fan Speed Controller Wiring Diagram
Wiring a fan speed control switch. Lutron skylark contour 15 amp single pole3 way quiet 3 speed fan control white model ctfsq fh wh 24 97 24 97. Variable speed controls must be specially designed for use with ceiling fans. Shop 48 7 results for fan controls. Although it seems to do a job similar to a dimmer and actually looks very similar the fan speed switch is more like a regular light switch and will be wired in series with the fan. There are several ways to control ceiling fans and light kits. Be aware that a standard light dimmer switch will not work with a ceiling fan.
The fan has power when the switch is on while the fan speed and the light if the fan has one are controlled by pull chains on the fan itself or by a remote control device. There are plenty of diagrams for wiring a single fan to a switch of this nature and plenty for wiring a single fan to a on and off switch with a separate speed control but none for two fans on a single fanlight control switch. Electrical wiring devices accessories lampholders floor boxes. This is actually a fairly simply switch that is mounted on the wall. Ceiling fan and light kit control options. One wireswitch to turn power onoff to the fan and lights at the same time two wireswitches one switch turns power onoff to the fan the other to the lights pull chains to adjust fan speed and lights remote control available on new or existing fans to adjust fan speed and lights.
A fan speed control switch makes it easy to adjust the speed at which a fan spins. Wall switch motion sensors motion sensor lampholder residential networking. Wiring devices light controls. Lutron diva 3 speed fan control with wallplate switch single pole white model dvwfsq fh wh 31 98 31 98. This electrical wiring question came from. Step 1 set up.
Start by turning off the light and ceiling fan at the fuse box. Leviton fan speed controls change the level of power in the fan motor to control the speed of your fan. With single switch wiring power to the fan is controlled by a standard single pole wall switch like a regular light switch. Eric a homeowner from pa pennsylvania. Wiring the fan to a variable speed control switch lets you make fine adjustments to the fans speed. In the above ceiling fan speed control wiring diagram i shown the main winding running winding and i connect run wire of motor to the speed control switch and you can see it in above diagram that connection of run wire of motor in switch l point and and 1 and 2 for capacitor.
Thanks for your help.