Mercedes-Benz ML500 Problem Report
Mercedes-Benz ML500 Airmatic Pump Relay May Stick and Cause Dead Battery
On vehicles with airmatic suspension, the airmatic pump relay can stick, causing a dead battery, because the pump continues to operate when it should be shut off. Eventually, the pump will fail; the pump, fuse, and relay will need replacement. After parking and exiting the vehicle, the airmatic pump should only run for a few seconds before turning off. It should not come back on until the driver's door is opened.