There is no direct connection from the purple wire to the ignition switch . This is computer controlled , Ignition switch is a low voltage input to the BCM - body control module . When you turn the key to start the BCM see's this an sends a message on the serial data network to the PCM / ECM - engine computer . IF the PCM / ECM see's voltage from the Internal mode switch in the transmission it knows it is in park or neutral an see's no problems with the anti- theft system it will energize the crank relay sending Battery voltage on the purple wire to the starter solenoid . You have no clue of the complexity of this system , do yourself a favor an take it to a qualified repair shop . Before you make matters worse . You already spent money on a new starter needlessly .
Circuit Description
Moving the ignition switch to the START position signals the body control module (BCM) through discrete inputs from the ignition transducer that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the engine control module (ECM)/powertrain control module (PCM) requesting engine start. The ECM/PCM receives a 12-volt signal from the park/neutral position (PNP) switch or clutch pedal start switch notifying that it is safe to start the engine. There is a splice on this circuit in the fuse block-underhood that supplies power for the starter relay coil. The starter relay coil control circuit is then grounded by the ECM/PCM closing the switch in the starter relay suppling 12 volts to the S-terminal of the starter. Ground is supplied through the engine block.
Vehicle Theft Deterrent (VTD) Description and Operation
Circuit Description
The Passlock?"¢ system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate. The Passlock controller reads the coded Passlock?"¢ data signal. The data consists of a voltage generated by a voltage divider network created between the Passlock assembly and the Passlock?"¢ controller. If the data is correct , indicating rotation of the lock cylinder with the proper mechanically cut key, then the Passlock?"¢ controller sends a password to the Powertrain controller over the class 2 bus to indicate that starter engagement should be allowed. The Passlock?"¢ controller also interfaces with the driver displays subsystem to indicate, via a Security telltale, the Passlock?"¢ subsystem's status and acute subsystem failures.
The components of the Passlock?"¢ System are as follows:
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The ignition switch
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The body control module (BCM)
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The security indicator on the instrument cluster
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The engine control module (ECM)
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