A car relay is an electrical switch that is used to control the flow of electricity in a vehicle. Relays are used in a variety of applications, including starting the engine, turning on the headlights, and operating the air conditioner. When a relay fails, it can cause a variety of problems, including the inability to start the car, the headlights not working, or the air conditioner not blowing cold air.
There are a few different ways to check a car relay. One way is to use a multimeter to test the continuity of the relay. Another way is to use a test light to check if the relay is getting power. If the relay is not getting power, then the problem may be with the wiring or the fuse.