Relays

Hey there everyone i feel that when a electrical system has a fault a lot of people check relays first. In my experience relays rarely fail. Not to say i havent seen it before
Relays are used throughout cars and trucks electrical systems. The purpose of a relay is to allow a low-amp circuit to control a high-amp circuit. Relays are just electronically controlled switches. You might find that one relay contains multiple relays inside of its housing. This is common in more advanced electrical systems. Usually a wiring diagram and terminal label will be printed on the outside of the relay. If not, try looking for terminals of the same color. This normally means that they are part of the same circuit. This information might not always work to be one hundred percent all the time but its how i have survived diagnosing for years
There are two basic parts to a relay: the coil and the switch. The coil is the control circuit and is used to activate the switch. It does this using the electromagnetic. Once the coil is energized, it creates a magnetic field, which closes or opens the switch. Some relays are normally closed and the activation of the coil opens the switch instead of closing it. This is where your wiring diagram comes in handy. Testing is fairly straightforward. Just activate the coil and check the resistance of the switch circuit