When the ignition is turned to the ON position, battery voltage is applied to cavity 12 of the cruise control servo through the closed contacts of the main relay. Ground for the cruise control servo is applied at cavity 11. Depressing and releasing the main cruise control switch closes the momentary switch contacts and signals the cruise control servo at cavity 8 to turn ON. The cruise control servo then grounds cavity 10 to turn ON the cruise control switch indicator lamp. The vehicle speed sensor (VSS) signal is applied at cavity 1 of the cruise control servo and allows it to monitor vehicle speed.

Operating the cruise control mode switch applies the following resistances between cavities 5  and 8 of the cruise control servo:

Whenever the cruise control system is in operation, ground from cavity 4 of the cruise control servo is applied to the CRUISE indicator in the Instrument Cluster.

When the brake pedal is depressed, one set of the stoplamp switch contacts close and applies B+ voltage to the brake lights and to cavity 2 of the cruise control servo which cancels the cruise control operation. The other set of stoplamp switch contacts open and removes B+ voltage from cavity 6 of the cruise control servo which removes voltage to the magnetic clutch in the cruise control servo.

Cruise control operation is also canceled when ground is applied at cavity 9 of the cruise control servo during the following conditions:

The Powertrain Control Module (PCM) provides a throttle position sensor signal to cavity 7 of the cruise control servo. This signal is used by the cruise control servo as one of the factors in determining when to provide an overdrive cutoff signal to the PCM.

When certain driving conditions exist which require the vehicle to shift out of overdrive, the cruise control servo sends an overdrive cutoff signal from cavity 3 to the PCM.