Bypass button press on fan for direct power on when plugged in
looking at the photo there seem to be some triacs (in semi-cylindrical TO92 packages) that do the actual switching of the current.

removing the circuit board, and connecting the white wires together and connecting the red power wire to either the back  high-speed or the red low speed terminal should get the fan motor running.







simulate this circuit &ndash; Schematic created using CircuitLab