If your Leviton VRI06 2 wire dimmer stops working, first check the breaker to ensure there is power to your circuit and it hasn't tripped. Next check the light bulb to ensure it is not blown. 2 wire dimmers work by passing a little current through the filament of the incandescent light bulb. This is why they are not compatible with LED or CFL bulbs. If the light bulb burns out, the filament is broken and the circuit cannot be completed, so the switch will also stop working.