I have removed old ceiling fan/light - fan quit working, not light. Checked all electrical circuits & GFCI for no problems - assumed fan wore out due to continuous use. Hanging new fan with light kit. Connections must be correct because light works, but not fan! Light on regular wall switch, fan on dimmer switch to choose 3 speeds. Wires from ceiling are green, white, red, black. I have white to white, green to green, ceiling red to fan blue, black to black. Why is fan not working on old or new?

Many fans will not run through a dimmer switch unless it is specifically designed for a motor. What type of dimmer are you using, or is it a 3 position fan switch?

Thank you for your help. The dimmer switch was on the old fan and it remains on the wall. It has positions to control fan for high-med-low-off.

Test the voltage out of the dimmer in the 3 positions. Measure voltage from the dimmer out across the neutral or ground. May be a bad dimmer.

Good idea. Will get around to that - hadn't thought of that part of the "journey".

That 3 step switch is not a dimmer. A dimmer switch is a full motion variable range switch. The control switch is designed and listed for the control circuit.

It works when the fan switch is left "ON" and in the "HIGH" speed.

The switch then controls the speed and On/Off of the fan. Make sure that the switch loop is properly wired. It would help greatly if you could post a pic. Of the ceiling wiring. I suspect that the problem is there.

You are correct that it is not a true dimmer switch like one used with chandeliers. It has positions "off-high-med-low-off".I took the 3-step switch off and wired a toggle switch on -bingo! Fan & light work. Will control fan speed from fan chain.