Why does electric fan and light click when power is turned on?
I am going to guess that you are talking about a ceiling paddle
fan with remote control (the remote being either hand-held or in
the wall box) The click sound you are hearing is likely the click
of the relay in the electronic control module inside the ceiling
fan. This module contains the actual power relay that turns the
power on and off. There is one relay for the fan and another for
the light. When you press the on-off buttons on the remote, it
sends a radio signal to the control module and activates the relay.
You can't hear the radio signal but you hear the relay click.