I have a 2008 e2 service manual. It is 7.5 meg, too big to attach here. give your email and i will send.
A constant beep when the brake is released is indicative of not having the key in the ignition. It sounds as if the switch in your key ignition is not connected. You need to check the connections on your ignition and your main connector, the switch in the middle of the dash that makes a loud click when the brake is turned off or the accelerator is depressed. Barring loose connectors, the next check is your controller.