Circuit Description
WARNING: This page is about a different car, the 2004 Chevrolet Monte Carlo and 2004 Chevrolet Impala. 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 PCM (CRANK) fuse in the Junction Block - Left I/P to the PCM to notify the PCM that a crank status has been requested. 12 volts is fed through the ABS/PCM fuse in the Junction Block - Left I/P to the coil side of the CRANK RLY relay. The PCM grounds this circuit when all parameters are met for starting the engine. This closes the CRANK RLY relay allowing Battery Positive voltage through Fusible Link and through the switch side of the CRANK relay to the S terminal of the starter solenoid. Ground is found through the engine block.