Door Jamb Switch

How Does a Door Jamb Switch Work?

The door jamb switch, also called the door jamb light switch or door ajar switch, controls your interior lights when your vehicle's doors are opened or closed. In some vehicles, door jamb switches can also trigger the door ajar warning on your dash if a door is not closed completely when the key is turned to the Run or Accessory position. This door jamb switch is typically mounted in the front of the door frame or built into the door latch mechanism. When you open your door, your door jamb switch is activated and the circuit is closed, illuminating your vehicle's interior lights. When you close your door, the switch is released, breaking the circuit and turning off your interior lights. Over time, door jamb switches can fail from repeated use, exposure to moisture or weather, or damage from a broken door hinge. If your interior lights aren't turning on when you open your doors, or aren't shutting off when you close the doors, you might have a faulty door jamb switch. If your vehicle's door jamb switch also controls your door ajar dash light or other warnings in your vehicle, you may notice random door ajar alerts. Some vehicles may also use separate switches for the interior lights and door ajar warning, meaning that these switches may need to be replaced separately. If you need a replacement door jamb switch or door ajar switch, O'Reilly Auto Parts carries replacement interior switches to help you complete your electrical system repair.