I am adding a ceiling fan to an existing junction box in my house. There was nothing there before, just a junction box which is rated for a ceiling fan. The house was built in 2016.
There is a standard switch that has Ground, a Line (live power) and Load wire going up to the fixture.
At the light fixture is the standard Ground, White, Black. But there is also a Red wire.
When the switch is off, both the black and red show ~2V (tested with a multimeter).
When the switch is turned on, the black wire shows 120V, and the red wire shows 12V.
There is definitely no red wire connected to this switch, so I am confused on why there is a red wire, and why it is showing 12V. Since it is in close proximity to the black wire, is it just picking up residual power?