What to know about the Speed Control Assembly:
Cruise control, or speed control, is used to maintain a set speed when driving at highway speeds. It not only relieves the driver from constantly pressing on the accelerator, but improves fuel economy thanks to less throttle fluctuation. The speed control assembly is a servo that works to hold the throttle steadily open when the cruise control is set.
It is a vacuum-operated component that has a chain or cable running between it and the throttle pivot. When the cruise control is set, the cable tightens to hold the accelerator position. Pressing the accelerate or coast buttons on the cruise control will increase or decrease the about of pull the servo exerts. If the speed control assembly or servo is not functioning correctly, the cruise control may not set at all or have difficulty maintaining a consistent speed.
Facts to Note:
The speed control assembly is also called the cruise control servo.
How to Fix:
The vehicle battery is disconnected for safety
The faulty speed control assembly is taken out
The new speed control assembly is fixed
The battery is reconnected and any programming is done
The vehicle is road tested and speed control operation is checked
The speed control assembly does not need upkeep or servicing, and should last the lifetime of your vehicle. If something does cause the speed control assembly to malfunction, or you suspect the speed control assembly is the cause of your cruise control issues, have one of your expert mechanics analyze and change it if necessary.
READ ALSO: WHAT IS ABS SPEED SENSOR REPLACEMENT
Common symptoms indicating you may need to change the Speed Control Assembly:
Cruise control will not set
Speed control will not maintain a set speed
Other vacuum-operated functions, such as heater controls, do not work correctly
Importance of this service:
Cruise control is not a mandatory part on vehicles, and many are still manufactured today without speed control. As such, it is an accessory. If it malfunctions, it should not present a safety risk. Don’t use the cruise control until you have the speed control assembly changed.