Headlight switches are designed to turn the headlights on and off. They are sometimes located in the dash or in combination switches like with the turn signal. It can be dangerous for the switch to go out, as the lights cannot be turned on or off. That can endanger the driver as well as some of the other components of the car. For instance, if the switch malfunctions during operation, the headlights may not turn off even when the engine stops. That will drain the battery and use the light unnecessarily. It is not an option to drive in the dark if the headlight switch is not working. The switch is not necessarily difficult to repair or replace. It depends upon its location. Switches in the dash may require the dash to be removed. Switches in the steering column may require the removal of the steering wheel. That may be more difficult because it requires specialized tools.