It is possible to destroy a 12 volt device by plugging it into a 24 volt supply. ... I ran tests on the battery and found that it had a voltage of more than 13 volts because of the constantly connected charger.
A 24 volt motor will likely run at half it’s designed speed when running on 12 volts, so it probably isn’t even worth plugging it in.
It is more than likely safe to plug it in, but because we don’t know how it is constructed it is impossible to say.
It does sound like it is the switch behind the control knob that is at fault. The fact that it is sometimes stiff would indicate a mechanical fault with the switch.
Are there electrical connections to a switch directly behind the control knob, or is there a mechanical mechanism that moves an electrical switch that is located somewhere else?
If the ...