Need help....have a 2003 E500 rear suspension problem...have no idea if it's pump, relay, auxiliary battery or leak. Car is currently practically sitting on ground in the back. I have tried for the last 2 weeks to start car and let run and nothing than yesterday went out to start and it came up, it will only up 24-48 hours. When starting the car I can hear pump clicking for a couple seconds and then shuts off. What's the first step to check to start so I can start ruling out things? Even though I am female I am very mechanically inclined being my father was a mechanic and I'm stubborn that way. Lol