2000 e320 want start

Hello, You should always begin by checking for trouble codes. Even if the check engine light is not on, there may be pending codes that can assist in diagnosing the vehicle. If there are no codes, check all of your fuses, listen for the fuel pump, and make sure the battery voltage is correct while cranking the engine. If everything checks out, and the vehicle still will not start, it is time to consult a professional, as changing parts in hopes that they will solve the issue becomes expensive quickly.