Circuit Description
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Normal vehicle Class 2 communications will not commence until the system power mode has been identified. Four discrete wires from the ignition switch contacts are monitored by the dash integration module (DIM) in order to determine the present power mode. The DIM communicates the system power mode to all Class 2 modules on the Class 2 serial data line.