Mazda Trucks 1994-1998 Repair Guide

Vacuum Controlled Systems

Print

See Figures 1 and 2

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



Control switches
 
Servo or vacuum actuator (throttle actuator)
 
Speed sensor
 
Stoplamp/brake switch
 
Actuator cable
 
Cruise control unit
 
Clutch switch (manual transmissions)
 
Vacuum dump valve (B Series Pick-up and Navajo)
 
Amplifier assembly (B Series Pick-up and Navajo)
 
Transmission range switch (MPV)
 

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 stoplamp 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: Typical vacuum operated cruise control system components-Navajo shown



Click image to see an enlarged view

Fig. Fig. 2: The cruise control vacuum servo unit is mounted on top of the right side strut tower in the engine compartment of the MPV

 
label.common.footer.alt.autozoneLogo