Why is my cruise control light always on?

The light staying on usually signals a fault in the cruise control system or a related sensor, so you should have the vehicle diagnosed soon. Do not assume it’s normal for the light to stay lit.

Cruise control indicators vary by vehicle. When the indicator remains lit even if you are not using cruise control, it typically points to a fault in the system or in one of its input sensors, rather than a deliberate setting. Potential causes range from a faulty brake switch to issues with the cruise control module, vehicle speed sensor, wiring, or throttle control. A diagnostic scan using an OBD-II reader can reveal trouble codes that identify the affected component.

Common causes of a cruise control light staying on

These are the most frequent culprits across many car makes and models. The indicator can come on due to a fault that the car’s computer has detected, or due to a signal it cannot correctly interpret.

• Faulty or misadjusted brake pedal switch (brake light switch): if this switch feeds the cruise control system, a fault can trigger the warning light or keep it on continuously.


• Cruise control module or actuator/sensor fault: a failure within the control unit, servo, or its sensors can generate a fault code that lights the indicator.


• Wiring, connectors, or fuse issues: damaged wiring or blown fuses to the cruise control components can cause the light to stay on.


• Vehicle speed sensor or ABS-related fault: incorrect speed data or ABS communication problems can cause the CC system to disable and illuminate the warning.


• Throttle control/ECU or electronic throttle body problems: faults in throttle control can affect cruise control operation and trigger warnings.


• Electrical system instability or power supply problems: battery/alternator issues or voltage drops can produce false fault signals.

If the light remains on, avoid relying on cruise control and seek a professional diagnosis to prevent unintended acceleration or loss of control. A dealer or qualified mechanic can pull codes, inspect the brake switch and sensors, and test the cruise control module.

How to diagnose and address the issue

Follow a structured approach to diagnose the problem. The steps below are practical guidelines you can use before taking the car to a shop. If you’re not comfortable performing these checks, skip to the professional diagnostics to avoid any risk.

1. Check that the brake lights illuminate normally when you press the brake pedal; a stuck brake switch can mimic a fault in the cruise control system.


2. Inspect fuses and relays related to cruise control and the brake switch; replace any that are blown or visibly damaged.


3. Use an OBD-II scanner to retrieve fault codes related to cruise control, throttle control, speed sensors, and ABS; record codes for reference.


4. Test the throttle/ETC system if your vehicle uses an electronic throttle; look for sticking or irregular idle as a sign of ETC trouble.


5. Verify the battery and charging condition; a low or unstable voltage can trigger fault warnings and affect the CC system.


6. If codes point to a specific component, arrange the appropriate repair and reset the system after the fault is repaired.

After repairs, the codes should be cleared and the indicator should be off when the system is healthy. If the light persists despite fixes, additional diagnostics focusing on the control module, CAN bus wiring, or other connected systems may be necessary.

Summary

A cruise control light that stays on is typically a fault indicator rather than a normal operating state. Common causes include brake switch problems, module or sensor faults, wiring or fuse issues, speed sensor problems, and throttle control faults. A diagnostic scan and checks of braking components, electrical connections, and the throttle system can identify the cause. Treat the issue promptly to avoid unsafe driving and consult a qualified mechanic if you’re unsure about performing the diagnostics yourself.

Why does my cruise control light stay on?

A faulty or misaligned brake switch can cause blinking cruise set lights and no key warnings. Inspect wiring connections near the brake pedal and test the switch for continuity. Cleaning or replacing the brake pedal switch often resolves the issue.

Why is my cruise main light on?

The "cruise main" light on your dashboard means the cruise control system is turned on and is ready to have a speed set, but a speed has not yet been set. If the light is amber or white, you're in this "ready" state; if it's green, a speed has been set and the system is active. If the light is on when it shouldn't be or is flashing, there could be a malfunction that needs professional diagnosis, possibly related to a sensor, fuse, or wiring. 
What to do
If the light is the color you expect (amber/white) 

• To engage cruise control, drive at your desired speed and press the "set" button. 
• The light will likely change color (to green) and the system will now maintain your speed. 
• To turn the system off completely, press the "on/off" button again, or the "cancel" button if you have one. 
• It's important to turn the cruise control off when not in use to avoid accidental activation. 

This video explains how cruise control works on a Honda, including how to engage it: 59sDmitry SapkoYouTube · Aug 31, 2024
If the light is stuck on, flashing, or the wrong color 

• This indicates a potential problem with the cruise control system. 
• Possible causes include a faulty brake pedal switch, a blown fuse, a malfunctioning speed sensor, or a problem with the system's wiring or control unit. 
• Have your vehicle inspected by a professional mechanic, as this could be an interconnected system issue and may require a diagnostic scan to identify the exact problem. 

This video demonstrates how to fix a cruise control light issue by checking the brake light switch: 1mDale of All TradesYouTube · Feb 14, 2024

How do I reset my cruise control?

How to Reset Adaptive Cruise Control

1. Step 1: Consult Your Vehicle's Owner's Manual.
2. Step 2: Start Your Vehicle.
3. Step 3: Access the ACC Menu.
4. Step 4: Select 'Reset' or 'Default'
5. Step 5: Press and Hold the Reset Button.
6. Step 6: Confirm the Reset.
7. Step 7: Monitor System Reset.
8. Step 8: Verify ACC Reset.

What would cause the traction control light to stay on?

A traction control light that stays on is usually caused by a faulty wheel speed sensor, but can also be due to the system being manually disabled, low tire pressure, a problem with the ABS system, or an issue with the steering angle sensor. A simple fix might be to press the traction control button to turn it back on or to restart the car, but if the light remains on, a mechanic needs to diagnose and fix the underlying issue. 
This video explains how to turn off the traction control light by manually disabling it and also covers faulty components: 59s8020 AutomotiveYouTube · Jul 27, 2025
Common causes

• Manually disabled: The system may have been turned off with the button on your dashboard and simply needs to be turned back on. 
• Faulty wheel speed sensor: This is a very common reason. Each wheel has a sensor that monitors its rotation. If one fails, the system can't work properly. 
• Dirt or debris: Dirt, mud, or brake dust can cover a wheel speed sensor, preventing it from reading correctly. Cleaning the sensor might fix the problem. 
• Low tire pressure: Incorrect tire pressure can cause the system to misinterpret readings and trigger the light. 
• ABS system issues: Traction control is closely linked to the Anti-lock Braking System (ABS). A problem with the ABS module, pump, or a related component can cause the traction control light to come on. 
• Steering angle sensor: This sensor tells the system which way the car is turning. If it's malfunctioning, it can confuse the traction control system. 
• Electrical issues: Problems with wiring, corroded connectors, or even low voltage from a weak battery can trigger the light. 
• Low brake fluid: In some cases, low brake fluid can affect the ABS and, consequently, the traction control system. 

What to do

1. Restart your car: Pull over in a safe place, turn the car off, and then start it again. The light may reset itself if the issue was a temporary glitch. 
2. Check for a manual override: Look for a button with an icon of a car with squiggly lines and press it to see if it turns off the light. 
3. Check tire pressure: Ensure all your tires are inflated to the correct pressure. 
4. Inspect sensors: If you are comfortable, check the wheel speed sensors for obvious dirt or debris and clean them. 
5. Seek professional help: If the light stays on after these steps, take the vehicle to a mechanic. The problem requires professional diagnosis, often with an OBD-II scanner, to read specific trouble codes and identify the faulty component.