Using the gas pedal allows you to speed up and control the car on the road, but it can be a chore when driving long distances on relatively flat roads with little to no other traffic. It can lead to fatigue, leg cramps and more. Speed control (also known as cruise control) is a convenience feature built into many of today’s cars that allows you to bypass manually using the gas pedal in these circumstances.

Your car’s speed control system allows you to set a speed and then have the computer maintain it. You can also speed up and slow down without pressing the gas or brake – you just need to use the cruise control selector to tell the computer what you want to do. You can even resume a previous speed if you had to turn off cruise control because of traffic. It also improves fuel economy, as the car’s computer is much more efficient than a human driver.

The key to the system is the speed control assembly. In new cars, it’s a computerized component that operates all aspects of your cruise control system. Like all other electronics, the speed control assembly is subject to wear and tear. One saving grace is that it’s only used when you turn on the cruise control system and set a speed. However, the more frequently you use the system, the more wear and tear it will sustain. In theory, it should last for the life of the vehicle, but that doesn’t always happen.

Older cars don’t use computers. They use a vacuum system and a servo/cable assembly to control cruise functions.

If your car’s speed control assembly is beginning to fail, you’ll notice a few telltale symptoms whether you have a newer computerized system or an older, vacuum operated model. These include:

  • Vehicle drops out of set speed for no reason (note that some cars are designed to drop out of cruise after slowing to a specific speed)

  • Cruise control does not work at all

  • The car won’t resume a previously set speed (note that some cars are designed not to resume a previous speed after slowing to a certain point)

If you’re experiencing any problems with your cruise control system, YourMechanic can help. One of our expert mobile mechanics can come to your location, inspect your vehicle and replace your speed control assembly if needed.

This article originally appeared on YourMechanic.com as How Long Does a Speed Control Assembly Last? and was authored by Valerie Johnston.


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