Ford Full-Size Vans 1989-1996 Repair Guide

Vacuum Controlled Systems


See Figure 1

The vacuum controlled cruise control system consists of the following components:

Control switches
Servo (throttle actuator)
Speed sensor
Clutch switch (manual transmissions)
Stop light switch
Vacuum dump valve
Amplifier assembly

The throttle actuator is mounted in the engine compartment and is connected to the throttle linkage with an actuator cable. The speed control amplifier regulates the throttle actuator to keep the requested speed. When the brake pedal is depressed, an electrical signal from the stop light switch returns the system to stand-by mode. The vacuum dump valve also mechanically releases the vacuum in the throttle actuator, thus releasing the throttle independently of the amplifier control. This feature is used as a safety backup.

Click image to see an enlarged view

Fig. Fig. 1: Vacuum controlled cruise control system components