Relay for compressor for Mercedes Benz W212 S212 and CLS C218 X218 Air suspension Please note that when shipping to a country outside the EU, you may Incur Additional Costs (Customs Duties, Vat). In order to ensure a safe functioning of a new compressor, the relay must also be replaced before installing the compressor. The relay offered is for the Mercedes Benz used. * You can find out the exact models and years of construction on the vehicle list listed above. Even if the installed relay is still functional, both we and the vehicle manufacturer are advising to change the work relay. Since the relays in the box are often very similar, make sure that the right relay is also changed. The most common cause of the defect of the compressors lies in a leak of the air spring system or the ent.