What is the Speed Control Assembly all about?
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 operates 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 working properly, the cruise control may not set at all or have difficulty maintaining a constant speed.
Keep in mind:
- The speed control assembly is also known as the cruise control servo.
How it's done:
- The vehicle battery is disconnected for safety
- The defective speed control assembly is removed
- The new speed control assembly is installed
- 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 maintenance or servicing, and should last the lifetime of your vehicle. If something does cause the speed control assembly to fail, or you suspect the speed control assembly is the cause of your cruise control issues, have one of our expert mechanics diagnose and replace it if necessary.
What common symptoms indicate you may need to replace 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 properly
How important is this service?
Cruise control is not a mandatory component on vehicles, and many are still manufactured today without speed control. As such, it is an accessory. If it does not work properly, it should not present a safety risk. Don’t use the cruise control until you have the speed control assembly replaced.