Checking air pump
Raise the car and remove the front splashguard, by removing the two screws on each side and then pull the guard and the bumper forwards until the guard can be lowered. Then remove the guard from the spoiler clips.
Disconnect both the remove connectors on the relay.
Connect both the blue wiring with a piece of cable or similar.
If the pump works now there is either a loose connection in the relay terminal or the relay is defective and should be changed.
CAUTION:
The pump should not be operated continuously for more than 120 seconds because of the risk of overheating.