Circuit Description
WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
Moving the ignition switch to the start position sends a 12 volt signal through the CRANK SIGNAL BCM, CLUSTER fuse in the instrument panel fuse block to the BCM, IPC and PCM to notify these modules that a crank status has been requested. At the same time 12 volts is fed through the PCM BCM U/H RELAY fuse in the instrument panel fuse block to the coil side of the STARTER relay. The PCM grounds this circuit, which passes through the Park/Neutral Position Switch, when all parameters are met for starting the engine. This closes the STARTER relay allowing battery positive voltage through the CRANK fuse and CRANK relay in the underhood fuse block to the "S" terminal of the starter solenoid. Ground is found through the engine block.