Mercedes-Benz W212 air suspension compressor not starting
Mercedes-Benz W212 air suspension compressor not starting and the rear stays down, where do I start?
First check whether the compressor is getting power. Its power runs through the fuse box next to the battery under the bonnet, and the small high-current fuse in that box may have blown. The fuse can also blow because the compressor has frozen up. Find out why it blew before fitting a new fuse.
Where is the W212 air suspension compressor relay and how can it be checked?
On the estate the relay is on the left side of the boot, on the saloon on the left side of the boot lid behind the panel. A click from the relay does not prove it works, because the contacts can stay open. Measure the relay terminals with a multimeter.
The fuse and relay are fine but the W212 compressor gets no power. What could be wrong?
The cause is often the wiring. Wires have been found broken at the connector and at the fuse box, and the compressor connector may have oxidised and melted. Oxidised wires at the air release and pressure relief valve have also prevented operation. Repair the wires and connectors before replacing the compressor.