What Are the Causes of Automotive Relay Failure?

[McEmersyn]

Below are the causes of automotive relay failure: 1. Incorrect auxiliary contact position: After multiple trips, the mechanical parts of the switch may shift or wear, causing the auxiliary contacts to deviate from their correct position. When the protection mechanism trips, if the auxiliary contacts fail to disconnect before the output device, electrical components, or relay return—meaning the intermediate device or relay contacts open before the auxiliary contacts—this results in the intermediate device or relay contacts being used to break the DC power supply, leading to burnout. Consequently, during a fault, although the protection mechanism activates, the switch fails to trip, causing an unintended cascade trip. 2. Stuck trip mechanism: Due to lack of maintenance, the switch mechanism may become stiff or stuck during operation, preventing normal tripping. This keeps the intermediate device or relay coil energized for extended periods, eventually burning out the coil and rendering the device or relay inoperable. 3. Trip coil core detachment or jamming: Repeated normal operations and fault trips can loosen the trip core’s retaining screw, causing the core to detach or jam. During a fault, the switch fails to trip, keeping the output intermediate device or relay energized for prolonged periods, which burns out the device or relay coil or contacts.