The Microwave Door Switch is an OEM replacement part for Samsung microwaves. This safety component plays a crucial role in ensuring the microwave operates safely and efficiently by detecting when the door is properly closed and allowing the microwave to function. Symptoms of a bad microwave door switch include: The microwave not starting or operating when the door is closed The microwave continuing to run even when the door is opened Error codes or warning lights related to the door switch Causes of a faulty microwave door switch can include wear and tear over time, misalignment or physical damage to the switch or door mechanism, or electrical malfunctions.3405-001034 (AP4044834) replaces 3405-000178, 2028597, PS4131192.