The oven door light switch is a on an off mechanism that will shut the oven light off when the door is closed or turn on when the door is open. When you open the oven door and the light does not come on, it could be the switch or the light bulb and one of them will need to be replaced. The light switch is black in color, 4 terminal double contact, and measures approximately 2 1/2” in length. Please remember to disconnect the power to the oven before starting the repair. This oven door light switch is a genuine OEM part.