The average car has hundreds of individual electronic or electromechanical devices within, some of which are far more complex than others and can be prone to failure from time to time. Many of these components are protected and only activated when they are required, and issues associated with these parts can often be traced back to the devices that regulate the connection. These devices are called relays, and it pays to understand what they do, how they work and what to do if they fail.

What Is a Relay?

A relay can switch its associated component on or off with a tiny amount of current and voltage. However, in doing so it enables the associated component to generate or regulate a heavy electrical load that would otherwise put a tremendous strain on the battery or other parts of the system.

How Relays Work

For it to work, the relay must receive this small amount of current through its solenoid, which will become magnetised and activate a plunger or rod to connect two main switches. These relays can be classified as 'normally open' or 'normally closed', and when the switches are activated, the primary component is live. However, as soon as the initial current is removed from the coil, the electromagnet will turn itself off and allow the main contacts to go back to their original position.

Protecting the System

Relays are crucial from a performance and safety perspective. Without them, a tremendous amount of heat will be generated in the circuit due to high levels of resistance. Furthermore, the battery could quickly become overwhelmed, as it would not be able to cope with the power drain.

What Can Go Wrong

While the relay itself is quite a simple device, it needs to be installed correctly and protected from external elements wherever possible. This means that it should not be exposed to dirt, debris or moisture and should be checked for functionality from time to time to ensure it can still protect the primary component. Therefore, if the air conditioning system or another major electrical item appears to be playing up, check to see if the relay is still working properly to start off with.

Getting Help

If this type of job is a bit too technical for you, bring in an auto electrical professional to help out. They will be able to get to the bottom of your problem quickly using special diagnostic tools and can ensure that you get back on the road without further delay.