Cruise Control: Description and Operation

The speed control system consists of:
- Speed control servo
- Speed control cable
- Vehicle speed sensor
- Horn relay and bracket
- Speed control actuator switch
- Stoplight switch
- Brake pressure control valve with integral deactivator switch
- Air bag sliding contact

The system operates independently of engine vacuum; therefore no vacuum lines are required.

The Speed Control Servo:
- Is mounted in the engine compartment near the power brake booster.
- Is connected to the throttle linkage with the speed control cable.
- Integrates system electronics, eliminating the need for any other speed control electronic modules.












The speed control actuator switch assembly is mounted in the steering wheel. It consists of:
- Control buttons (ON, OFF RESUME, SET, ACCEL and COAST).
- Necessary wiring.

The Vehicle Speed Sensor
- Is mounted to the transmission.
- Is a magnetic pickup driven by a gear. This gear is driven by the transmission.
- Sends a signal to speed control servo in proportion to vehicle speed.

The air bag sliding contact:
- is located at the center of steering wheel behind the driver air bag module.
- transfers electrical signals from the steering column wiring to:
- Driver side air bag module
- Horn blow switch
- Speed control actuator switch.

The stoplight switch:
- Is a normally open switch that closes when brake pedal is applied.
- Sends an electrical signal to the speed control servo to disengage the speed control system.
- Returns to its open position when the brake pedal is released.

The deactivator switch:
- Is a normally closed switch. Replaces the speed control dump valve as a redundant safety feature in the system.
- uses an electrical signal from the stoplight switch circuit to the speed control servo to disengage the system when the brake pedal is applied.
- Under increased brake pedal efforts (22.25-44.5 N [15-10 Lbs]), engine running), the deactivator switch mounted in the brake line will open and remove power to the speed control servo, releasing the throttle from speed control servo control.
- Is located at the rear brake pressure control valve (anti-lock brakes) or brake pressure switch adapter (conventional hydraulic brakes) below the power brake booster.
- Is mounted to end part of the brake pressure control valve. The brake pressure control value is mounted in-line to the rear brake hydraulic lines.







The electronic instrument cluster consists of one microcomputer-based module that processes sensor information and controls the three vacuum fluorescent displays. The displays includes:
- Speedometer/odometer
- Electronic fuel and engine coolant temperature gauges
- Message center

The message center includes the SPEED CONTROL SET indicator. This indicator:
- Indicates to the driver that the speed control system is maintaining vehicle speed.
- Illuminates when the speed control is actuated and when RESUME is actuated.
- Turns off when the brake pedal is applied and/or when the speed control OFF switch is pressed.