The electrical Mercedes-Benz Relay is the reason each of the accessories the driver enjoys can be successfully active. The relay is a multi functional apparatus that not only is used to initiate an electrical component but can also reduce the amount of voltage so specific power requirements can be met for individual devices.
The most frustrating thing in relation to the relay on a Mercedes-Benz for the owner is the location of them. The infrastructure of the electrical system on your vehicle is not very large. Because of this the degradation of the electrical impulse from one end of the vehicle to the other is negligible. It is relatively easy to locate a functioning relay of an electrical device because when it is activated because the lever inside of it moves and makes a metal to metal contact that initializes the electrical flow. This movement makes a clicking noise, even if it is so slight. When a Mercedes-Benz relay is faulty, it no longer makes this noise and finding its location can prove to be difficult. The correct one could literally be anywhere on the Mercedes-Benz.
Most of these electrical devices are relatively close to the device they are initialing but not all of them. For devices under the hood, there is generally more space to place them near the device. For components in the passenger compartment, this is not always the case.
Somewhere in the dashboard or on the fuse box is where most of them are located, but any of the devices from the rear of the vehicle are also located here. This is why locating a faulty relay on your Mercedes-Benz might be more time consuming than you might think. Once found it is a simple unplug and plug in the new one.