Internal on/off switch for a ceiling fan light. To fix and replace a bad on/off light switch inside the ceiling fan: 1  Remove the light fixture housing from the fan. 2  Unscrew the screws where the light fixture attaches to the fan assembly. 3  The small switch where the pull chain attaches should now be visible.4  Remove the old switch.lways turn off power before taking apart a ceiling fan or light switch. Pull chain for a ceiling fan light switch. To replace the fan light switch pull chain: 1  The switch housing needs to be removed. 2  Unscrew the screws holding the lighting assembly to the fan.