It is the Volkswagen Relay that all electrical voltage goes through before it reaches it destination of activating an accessories on your vehicle. Inside of each relay on every Volkswagen is a metal bar that moves when an electrical current is sent to it. This movement is the clicking noise that is heard when a Volkswagen relay is activated.
There are multiple reasons for the relay to be used in the wiring harness on your vehicle. Not only can it be used to initiate many different components at the exact same time, but it also regulated the amount of voltage an electrical device will receive so it will not be burnt out by a too high of a charge.
The relay in the electrical system on your Volkswagen is also in place as a safety device. If there is a surge of high voltage through your wiring harness, it is the relay that will absorb this extra voltage and become burned out. This way the electrical devices in your vehicle are protected in a similar manner as what the fuse provides for the system. This way the replacement and repair costs are significantly less.
The number of these electrical switches is so numerous there is not just one location for them to be found. Since the electrical charge flowing through your wiring harness does not depreciate over its system, they can be literally anywhere on your Volkswagen and still be capable of performing its task of initiating an electrical device. Because of this, replacing it is simple, once the correct one has been located. The easiest way to locate them is to ask an experienced technician or refer to a service manual for your model of vehicle you own.