Cruise Control: Description and Operation

The speed control system consists of:
^ Speed control servo
^ Speed control actuator switch
^ Brake on / off (BOO) switch
^ Deactivator switch (Part of BOO switch)
^ Speed control cable
^ Vehicle speed sensor (VSS)







The electronic speed control amplifier is integrated into the speed control servo.

When the operator depresses the ON switch, the speed control servo receives a 12 volt signal through the air bag sliding contact to the ON switch. This signal causes a "power on" memory in the speed control servo. The CST, SET / ACC and RSM switches connect through resistors of various sizes. The speed control servo can determine the switch depressed by the voltage drop across these two circuits.

The speed control servo receives battery voltage. Ground is supplied through the powertrain control module (PCM). The speed control servo controls vehicle speed through a motor driven cable to the accelerator pedal assembly. The speed control servo determines control from operator input (switches) and vehicle speed sensor. Speed control is temporarily shut off (memory saved for RSM function) when a 12 volt signal is received from the BOO switch.

The deactivator switch is part of the BOO switch as a redundant safety feature. This is a normally closed switch. When the brake pedal is depressed, the deactivator switch provides a 12 V signal to the speed control servo.

The speed control system is shut off completely (no-memory) by depressing the OFF switch or by turning the ignition switch OFF.