If you are experiencing problems with your cruise control system, there are ways to identify and address them before they have a chance to worsen. Whether your cruise control system is having difficulty maintaining a constant speed or completely nonfunctional, here are some ways to determine what the issue is.
How a Cruise Control System Should Work
Cruise control systems are supposed to maintain a constant speed in your vehicle. Pressing the SET button keeps the car at whatever speed you’re currently at until you step on the brake pedal, or you press the CANCEL or OFF buttons. If you press RESUME, the car will accelerate or decelerate to the speed previously set. You can also choose to decrease the vehicle’s speed through the use of DECEL, COAST or (-) buttons. Keep in mind that cruise control systems normally only work once the vehicle exceeds speeds of 25 to 30 mph, and can’t be set to speeds any lower.
Common Cruise Control Issues
When trying to identify a specific problem when your cruise control system isn’t operating the right way, it’s important to consider some of the more common problems.
One common issue is a blown fuse. Shorts or electrical overloads in cruise control circuits can cause the fuse to blow. You can figure out the location of the fuse by looking in your owner’s manual. If you find that the fuse is blown, replace it with a fuse that has the same amp rating. Using fuses with higher amp ratings can result in overheating and a subsequent fire hazard.
Misadjusted or Broken Brake Pedal Switch
Another common problem involves brake pedal switches. If your brake lights don’t turn on when stepping on the brake pedal, it could indicate a faulty brake pedal switch if it shares the same switch with the cruise control. Some vehicles contain two brake pedal switches. Misadjusted switches will also prevent the cruise control system from working correctly.
Faulty Vehicle Speed Sensors (VSS)
Cruise control systems can’t operate correctly without a good speed input. A faulty vehicle speed sensor will not allow the speedometer to work, either, so if your speedometer is working correctly, this likely isn’t the issue.
Faulty Wiring or Cruise Control Switches in Steering Wheel or Column
If you find that certain buttons on your cruise control panel work while others don’t, the problem is likely to be the switch. If none of the buttons work, then it’s likely the wiring that is the culprit. Repairing either will require the removal of the steering wheel, which you should only do once you’ve deactivated the air bag system to avoid accidental deployment.
Faulty PCM or Module
If your Check Engine light is on, this could be related to a cruise control issue. If you find a code that indicates a cruise control module fault, then you should check the module’s power and ground connections. If the connections aren’t the problem, you should replace the module.
Faulty Vacuum Actuator
Older vehicles with electromechanical cruise control systems might experience failure with the vacuum actuator. Leaky vacuum connections can also cause problems, along with a faulty vacuum control solenoid. With any of these problems, replacing the vacuum actuator is required.
Faulty Throttle Actuator
If the motor that opens and closes the throttle is faulty, the engine will likely stay idle. The Check Engine light will also probably activate, and codes will be set for the throttle control system or the actuator.
These are simply some of the many issues you may experience. If you can’t determine the cause for any issues, you should consult an auto expert to help you diagnose the issue and fix it, or you can replace the entire unit with a compatible cruise control system from an online store.