Dimmer Switch: Testing and Inspection

INSPECT LIGHT CONTROL RHEOSTAT OPERATION
a. Connect the positive (+) lead from the battery to terminal 1 and the negative lead (-) to terminal 3.
b. Connect the positive (+) lead from the voltmeter to terminal 2 and the negative lead (-) to terminal 3.
c. Turn the rheostat knob and check that the voltage changes.
If operation is not as specified, replace switch.