The most common application of automotive relays; is to switch a high current circuit, using a low current circuit.
This application comes into play whereby, an in-line switch does not have the capacity; to handle the current required to switch a high current electrical system.
For example, this scenario could be observed during the operation of, a fuel pump or engine cooling fan.
So, a key advantage of using automotive relays is; that it allows the activation of multiple circuits, from a single switch. As a result, a single input within an electrical system, can be used to activate and trigger; multiple relays installed in an electrical circuit. These automotive relays can then complete/ break multiple circuits and therefore; execute multiple functions, given a single input signal.
A simple real life example, from a single switch is; the central locking system in a car. A single button press, results in all the door locks, locking or unlocking. Simple, time-saving and effective. And, most of the time, not even thought off.
The Fastest Way, To Test Automotive Relays
One of the fastest ways to test a relay is, firstly, remove the suspected relay. Put the new relay of the same size, shape, and pin arrangement.
TIP: Sometimes there is more than one relay, in your fuse box; with the same configuration, as the suspect one. If so, remove and try that relay first. You could make the diagnosis. that much faster.
Check if the accessory works, if yes. Then the original automotive relays is bad.
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