I installed a 3 speed ceiling fan with a dimmable light in the bedroom where a standard 2-wire light fixture used to be. After months of unsatisfied performance of these battery operated wall switches, I would rather have a full functioning wall switch. I have access to the junction box and all wiring for the fixture since the attic is above the ceiling. Is there a way for me to add a 3rd wire or change the wiring from the switch to the fan/light so I can install a 3 wire wall switch?
pull the third wire (same gauge) through the same conduit from the fan to the switch. It possible that the conduit isn't large enough for another wire and you'll need to upgrade it. Use either red or black but make sure you can distinguish the 2 lives (like if you end up with 2 blacks you label that wire at both ends).
You then either need a second switch so one controls the light and the other the fan. Or if it is pullcord operated then the new wire will need to always live; just hook it up before the switch.