Cruise control is a great feature that some cars have to help you maintain your car’s speed without accelerating. However, cruise control is not perfect, as something can go wrong and keep it from functioning.
When your cruise control is not working, you may be wondering what caused it. I looked up the facts, and here is what I learned!
Cruise Control Not Working? (11 Reasons Why)
1. A Blown Fuse
One of the most common reasons why your cruise control stopped working is that you have a fuse blown out.
Generally, all of the electrical systems in your car will be controlled by fuses, which is in charge of protecting the main electrical component.
When there is a fault or short circuit, the fuse is meant to blow to protect the major electrical parts from damage.
However, a blown fuse will also keep the electrical systems like cruise control from working because no electricity will reach them.
2. Bad Speed Sensor
Usually, cruise control is meant to help you maintain your car’s speed without accelerating, so having a bad speed sensor can make your cruise control malfunction.
A speed sensor is responsible for measuring the wheel speed or transaxle or transmission output.
As such, the speeds sensors try to see if the car needs traction control, which is crucial for cruise control.
Normally, your cruise control will not work or even malfunction when the speed sensors are faulty because it cannot accurately measure the car’s speed.
Moreover, you will be able to tell if there is an issue with your speed sensors when your speedometer acts oddly or gives inaccurate readings.
Additionally, issues with the speed sensors will also trigger a check engine light or ABS warning light on your car’s dashboard.
3. Faulty Brake Pedal Switch
Usually, having a faulty brake pedal switch is the main reason why your cruise control would stop working.
Generally, your brake pedal switch is in charge of switching the brake lights on and off depending on the pedal’s position.
Usually, the designs for cruise control systems involve the cruise control disengaging whenever you press on the brake pedal.
So since the brake pedal switch is connected to the cruise control, having a faulty brake pedal switch can make your cruise control stop working.
For instance, your car may think that the brakes were engaged when the brake pedal switch malfunctions, making the cruise control automatically switch off.
Another way to tell that you have a faulty brake pedal switch is when your brake lights turn on and off randomly.
4. Bad Vacuum Actuator Or Cable
If you happen to have an older car that has cruise control, chances are that your cruise control does not work because of a problem with a throttle cable or vacuum actuator.
Normally, having any issue with the actuator will make the cruise control malfunction.
Moreover, the cruise control usually fails when the cable that links the actuator to the car’s throttle has been damaged.
5. Damaged Relay
While not all cars have this, some cars will have relays that protect the circuit of the cruise control actuator.
A relay is a type of electric switch that closes and opens the circuit, which means a relay operates similarly to a switch.
If your car’s cruise control has a relay that is damaged, your cruise control will not work because the relay will not open and close the circuit when you use it.
6. Brake Lights
If you recently blew a brake light, there is a good chance that your cruise control does not work due to a blown brake light.
For some car systems, the cruise control will get disabled when one or multiple brake lights blow.
Normally, this can occur because you have had your brake lights for a long time, so they would have burned out.
However, getting aftermarket lighting like LED brake light conversion could be the cause as well.
For instance, aftermarket lighting may not be completely compatible for your car, so it would trick the central control module into believing there is a blown brake light.
So even if your brake light is not blown, your central control module would think it is and make your cruise control malfunction.
7. Faulty Spiral Cable
For most cars, the cruise control switch is mounted on the steering wheel, which is where you can find a spiral cable.
Occasionally, the spiral cable can be faulty, which creates an open circuit that keeps your cruise control switch from contacting your car’s central control module.
Normally, this can be fixed by having a mechanic replace the spiral cable since you usually cannot repair the spiral cable.
8. Electrical Issues
Generally, cruise control systems in cars are electronic, which means there are various components that work together to make the cruise control system operate.
As such, any problem with the electrical components in the cruise control is a common reason why your cruise control would stop working.
Normally, one of the more common electrical issues that can occur with the cruise control is that you have a faulty connector or wiring harness in your cruise control system.
Next, the next issue that can occur is that your voltage source may not be giving enough power to the cruise control system.
Additionally, the cruise control may not work because it is not being engaged, which normally happens when you have a defective cruise control button or switch.
Ideally, it is best to have a mechanic look for electrical issues with the cruise control to repair any wiring issues.
9. Check Engine Light
If you have a modern car, especially a car with electronic throttle control, your check engine light may be keeping your cruise control from working.
Generally, having a problem with your transmission or engine will disable your car’s cruise control.
Usually, your engine’s control unit will disable the cruise control once it detects an issue with your transmission or engine as a safety precaution.
If you notice that your check engine light goes on, your cruise control light will also blink to alert you that the cruise control was disabled.
In some cases, your car’s dynamic stability control light may also switch on to signal that it has been disabled when the check engine and cruise control lights illuminate.
10. Control Switch
Normally, most cruise control systems turn on and off the cruise control, so having a defective control switch could make your cruise control stop working.
For control switches, there are internal contacts that turn the cruise control on and off whenever you press a button or flip a switch.
When these internal contacts get worn out, your cruise control switch will not be able to contact the central control module.
Therefore, the cruise control system would not react to accelerate or cancel functions, or the cruise control may get disabled altogether.
Typically, this can be fixed by finding a new control switch to replace the worn out contacts on the faulty control switch.
11. Vacuum Leak
As stated earlier, having damage in your actuator or the cables of the actuator can affect your cruise control, and so can a vacuum leak.
There are tubes or hoses in the actuator, and they can occasionally get a leak that can make the cruise control stop working.
Normally, there are other signs that you can watch out for if you have a vacuum leak, such as noticing the engine sets a fuel trim code or your engine idlers higher.
Conclusion
Typically, cruise control will stop working because there is a different issue in your car, such as a transmission or engine problem.
However, having an issue with your brakes or the cruise control system itself can make your cruise control malfunction.