A relay switch is an electrical device that opens and closes circuits by using an electromagnet to operate a set of contacts. Relay switches are used in a wide variety of applications, including electrical circuits, industrial automation, and telecommunications.
To check a relay switch, you will need a multimeter. First, set the multimeter to the ohms setting. Then, touch the probes of the multimeter to the terminals of the relay switch. If the relay switch is working properly, the multimeter will read 0 ohms. If the multimeter reads infinity, then the relay switch is not working properly and will need to be replaced.