An Introduction To Cruise Controls

When you’re driving on long stretches, maintaining the speed of your vehicle can be tedious. Most cars, even those you buy used, are now equipped with cruise control systems. Their job is to alleviate the need for your constant pressure on the gas pedal to maintain a given speed. It accomplishes this by controlling the throttle, thereby simulating your pressure on the pedal.

Cruise controls have varying options, but most allow you to accelerate or decelerate by tapping a button. They also come with a “resume” function that allows the driver to engage the system after turning it off by hitting the break pedal. Below, I’ll describe a few of the parts that are used and some of the problems you may experience.

Parts Of The System

There are a number of components that work together in a cruise control unit. They include an actuator, brake and clutch switches, speed sensor, throttle link, and a cruise control module (CCM). The actuator is what controls the throttle link, simulating your foot’s pressure on the gas. The brake switch is responsible for sending a signal to the CCM to disengage when you press your car’s brake pedal. Clutch switches are used in cars with a manual transmission. Like the brake switch, it tells the CCM to turn the system off when you press the clutch in.

The speed sensor does exactly what its name implies. It sits on the transmission and sends a continuous current to the CCM. The CCM monitors the current and adjusts your car’s speed according to the speed you set the system to. The throttle link, as described above, is controlled by the actuator. Finally, the CCM oversees the entire operation. It constantly compares the speed sensor’s current with the original speed you programmed. Then, it tells the actuator to move the throttle link to adjust for variances.

Potential Problems

Occasionally, your cruise control system can fail to operate properly. Each automaker designs them a little differently, so it’s possible that the root cause is exclusive to your make and model. You’ll probably need to take your car to a mechanic to see what is causing it to malfunction. Most technicians will have diagnostic charts that they can use to find the cause.

The most common problems are related to blown fuses which can be repaired easily. Otherwise, the speed sensor can malfunction which will affect the CCM’s ability to control the actuator effectively. Also, it’s common for a vacuum leak to develop in the actuator. If the leak is large enough, the actuator will lose its ability to control the throttle link.

Cruise control systems are a fantastic invention that provides millions of drivers with relief on road trips and other long drives. You now know the basics regarding how they work. If your system fails, take it to a trained technician who can identify the cause quickly.

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