Cruise control has been around since the late 1950s. There was a time when you could only find this convenient feature in a few model vehicles. Nowadays, it seems like virtually every model vehicle on the road has a cruise control feature.
Cruise control not engaging seems like a trivial issue, but the inability to activate this convenient feature can certainly dampen any road trip. While cruise control failures “rarely” pose safety risks, determining the root cause is necessary to restore its use. Let’s look at the common causes of cruise control malfunction.
Cruise Control Problems (Accelerating or Maintaining Speed)
If your cruise control feature malfunctions and stops working altogether, you may not think it’s an immediate concern. You’ll probably figure that you just can’t use cruise control anymore until you get the problem fixed.
However, the problem with your cruise control might be related to an acceleration issue too. In fact, there are components of cruise control which can have an adverse effect on the acceleration if those components are bad. That is why you need to be aware of what causes cruise control issues.
Common Causes of Cruise Control Not Working
There are several possible causes of cruise control not working. Below are the top 6 most common causes. Check each of these areas and see if they’re the cause of your cruise control issue. In many cases, the remedy to the problem is not that complicated or expensive.
1) Cruise Control Switch
The cruise control switch is what you use to set your cruising speed. This information is transmitted to the engine control unit and cruise control module in order to sustain the acceleration speed.
If the contacts inside the cruise control switch were to wear out, then the module and unit might not receive the necessary speed information it needs to keep the acceleration going. In response, the system will deactivate entirely and cancel the current cruise acceleration set.
2) Brake Light Switch
Normally, you press the brake pedal to turn off cruise control. The brake light switch must be detected by the cruise control system for this to happen.
If it cannot detect the switch, then cruise control will disable itself automatically until the brake light switch issue is fixed.
A faulty brake light switch can also cause your brake lights to stay on.
3) Blown Fuse
The electrical components of the cruise control system are protected by fuses. Like inside your house, it is possible to blow a fuse. This will cause the cruise control system to turn off until the fuse is replaced.
4) Check Engine Warning Light
If the check engine warning light comes on, it usually means there is a problem with your transmission or engine. Once the engine control unit detects this problem, it may disable your cruise control system in response as a safety precaution.
Until you fix the engine issue, the cruise control will stay disabled.
5) Vehicle Speed Sensor
Most vehicles have a few vehicle speed sensors to transmit speed information about the vehicle to the engine control unit and the cruise control module. The only way your cruise control module is going to know how fast the vehicle is moving is if the vehicle speed sensors feed this information to it.
If the module cannot detect the speed because of faulty speed sensors, then the cruise control system will automatically deactivate.
6) Electrical Issues
There are several electrical components connected to the cruise control system. The connectors and wiring harnesses, and ground straps are definitely components that you need to check when the cruise control stops working.
Make sure the source of the voltage is still supplying power to the system as well. If any of these components are loose or damaged, then it would explain why the cruise control isn’t functioning.
7) Loose or Broken Cruise Control Cable
Older vehicles that are equipped with cruise control have two throttle cables – one for the gas pedal and one for the cruise control system.
These cables may stretch over time. If the cruise control cable has stretched or is broken, the cruise control system will not be able to operate the throttle plate properly.
Adaptive Cruise Control Specific Problems
Adaptive cruise control gives an extra layer of convenience while driving, as it adjusts your vehicle’s speed based on the distance to the car in front of you. However, this presents additional causes of cruise control failure.
One issue you might face is obstructed sensors. Both radar and cameras are important components of the adaptive cruise control system. When there’s dirt, debris, or ice covering these sensors, your cruise control can stop functioning. To prevent this, regularly clean your vehicle’s sensors, making sure they’re unobstructed.
Separately, failed cameras can also be a culprit. If the cameras aren’t working correctly, you may see an error warning. It’s best to get this checked by a professional to determine whether the cameras need repair or replacement. Hopefully it’s not as they are an expensive replacement.
Apart from cameras, adaptive cruise control relies heavily on radar technology for proper functioning. A misaligned or malfunctioning radar sensor can cause your system to behave irregularly. Again, consult a qualified technician to diagnose the issue and, if needed, recalibrate or replace the radar system.
Safe Driving Without Cruise Control
When cruise control systems fail, it presents challenges adjusting to speed management without the consistent pacing it provides. But there are a few things you can do.
- Focus on scanning gauges more frequently to stay actively aware of mph.
- Avoid zoning out on long hauls.
- Set phone alerts every few miles to remind checking current travel speed.
- Know highway speed limits well so mentally benchmarking against them continues subconsciously.
- Take frequent breaks stretching legs to re-energize alertness until able to diagnose cruise faults.
- Consider alternative adaptive cruise technologies equipped on newer vehicles if financially viable, providing automated incremental slowing when closing distances on lead cars.
- Remain vigilant of lead car distances and your own speed fluctuations.
- Utilize open lanes with fewer surrounding vehicles if possible, reducing needs for continual minor adjustments.
- Stay alert with renewed attention and defensive awareness absent cruise controls automated convenience until repairs are completed.
Intermittent Fault Identification
When cruise controls experience occasional yet repeating failures, meticulously logging every instance of malfunction helps uncover patterns guiding toward root causes.
Date and time each cutoff or disengagement that happens while activated. Detail any environmental or operational conditions present such as: weather, bumpy vs smooth roads, stop & go traffic versus highway speeds.
Reviewing complete repair histories alongside these event logs indicates if previously replaced components only provided temporary fixes before subsequent re-failure later on. Share documented patterns of when and how interruptions occur with shop technicians to guide their pathway tracing and component testing.
The goal is determining if specific elements like an old switch, wire insulation or solder joint chronically breaks down only under certain temperature, vibration or usage strain thresholds.
Cruise Control Repair Costs
So, your cruise control decided to take a break, and now you’re wondering how much it’ll cost to fix it. Well, repair costs vary depending on the specific issue and your vehicle’s make and model. This section will provide you with an idea of what to expect in terms of expenses.
Let’s look at the common reasons for cruise control problems and their approximate price range for replacement or repair:
- Faulty Cruise Control Switch – $100 – $200. A bit more expensive than a brake light switch.
- Blown Fuse – $5 – $30. Quick and affordable to replace.
- Faulty Brake Light Switch – $50 – $150. Can be a bit pricier but still manageable.
- Defective Speed Sensor – $100 – $300. Falls somewhere in the middle of the price spectrum.
- Throttle Control System Issues – $200 – $600. More expensive to diagnose and fix.
- ABS-related Problems – $200 – $1,000. Can also be quite costly to repair.
- Broken Vacuum Line – $50 – $150. Applicable to older systems and typically inexpensive to fix.
How Does Cruise Control Work?
If you normally drive long distances, especially on the interstate, then cruise control lets you take your foot off the gas while the car maintains the same speed, giving your leg a rest. This may seem like merely a luxurious feature rather than a necessity, but many people depend on it for safe driving.
There are several different types of cruise control systems, but all implementations share similar basic components. There is a sensor to measure vehicle speed, a throttle position sensor, and some mechanism to control the throttle plate without the use of the gas pedal.
Outputs from the speed and throttle position sensors allow the engine computer to determine how much the throttle plate needs to open or close to maintain speed.
Cruise control systems may also use sensors in the transmission, taking the current gear and engine vacuum into account. Throttle position will be different in each gear at a given speed, especially when driving over hills.