The Interlock Switch is an OEM replacement part for GE dishwashers. It is an electronic sensor located inside the dishwasher door that detects when the door is securely closed.  Symptoms of a bad Interlock Switch include: The dishwasher will not start a cycle even with the door closed   Error messages related to the door being open displayed Failure to advance through cycle selections Inconsistent or unreliable door closure sensing Causes can be normal wear and tear over extended use. Moisture exposure inside the dishwasher environment may also contribute to switch malfunction over time. This OEM part is also compatible with some Hotpoint, RCA and Kenmore branded dishwashers.Part Number WD21X10224 (AP3872949) replaces 1168295, AH1021382, EA1021382, PS1021382.