Cruise Control: Description and Operation
DESCRIPTION & OPERATIONThis system consists of an electronic servo assembly, actuator cable, horn relay, steering wheel switches, brake lamp switch and a deactivator switch. The system operates independent of engine vacuum, therefore no vacuum lines are necessary. The servo is mounted near the brake booster and is connected to the throttle linkage with an actuator cable. The electronics are integrated into the servo, eliminating the need for any electronic modules in the vehicle.
The deactivator switch is a normally closed switch and replaces the vacuum dump valve as a safety feature in the system. On a vacuum operated system, when the brake pedal is depressed an electrical signal from the brake lamp circuit will disengage the system. On this system, under increased brake pedal efforts (5-10 lbs.), the deactivator switch will open and remove power to the speed control servo clutch, releasing the throttle independent of the amplifier control. The deactivator switch is located at the rear brake proportioning valve below the brake booster.
System Activation
To operate the speed control system, vehicle speed must be greater than 30 mph. At this time, the system is activated and is ready to accept a set speed signal by pressing the ON and SET ACCEL switches on the steering wheel. This will set speed at its current speed until a new speed is set by the operator, the brake pedal is depressed or the OFF switch is depressed.
Decreasing Set Speed
Vehicle speed may be reduced in three ways; applying the brake pedal and then resetting the speed using the system activation method, depressing the COAST switch, tapping the COAST switch (Tap-Down). When reducing the speed by depressing the COAST switch, hold the COAST switch down until vehicle is slowed to the desired speed, then release the COAST switch and the new vehicle speed is set automatically. To reduce vehicle speed using the Tap-Down method, tap COAST switch once for each 1 mph until vehicle reaches desired speed. If the vehicle speed is reduced below the minimum operating speed, the operator must manually increase the speed and reset the system.
Increasing Set Speed
Vehicle set speed can be increased in three ways: manually using the accelerator, pressing the SET ACCEL switch, tapping the SET ACCEL switch (Tap-Up). To manually increase set speed, depress the accelerator until the higher speed is reached and stabilized, then depress and release the SET ACCEL switch. Set speed can also be increased by depressing the SET ACCEL switch and holding it in that position, vehicle speed will then automatically increase, when desired speed has been obtained, release the switch. To increase vehicle speed using the Tap-Up method, tap the SET ACCEL switch once for each 1 mph until vehicle reaches desired speed.
Resume
When the speed control system is deactivated by depressing the brake pedal, the set speed prior to system deactivation may be reset by momentarily depressing the RESUME button. The RESUME function of the system will not function if the system is deactivated using the OFF switch, or if vehicle speed has been reduced below the minimum speed of 30 mph.