Can a blown fuse cause cruise control to stop working?

Yes. A blown fuse can disable cruise control by cutting power to the cruise control module or its control circuits, though other issues can also keep it from functioning.

Understanding how cruise control is powered

Cruise control is not a single device; it’s a system that includes a controller, an actuator or throttle control, and wiring connected to speed sensors and brake or clutch switches. Power for these components typically runs through dedicated fuses and relays in the vehicle’s fuse box. If the fuse feeding the cruise control circuit blows, the system will not engage or will disengage when you press the set button.

Power sources and fuse placement

Power for the cruise control circuit is routed through specific fuses (and sometimes a relay) in the car’s fuse panel. The exact fuse label and amperage vary by make and model, so consult the owner’s manual or the fuse box diagram for your vehicle. A blown fuse can mimic a full system failure even if other engine systems operate normally.

Common fuses to inspect

Before checking these fuses, know that some vehicles route cruise control power through the main engine-management circuit. Look for fuses labeled specifically for cruise control and for fuses that feed the engine control module, as these can influence the cruise system even if they aren’t labeled “cruise.”

• CRUISE CONTROL fuse: Labeled as “CRUISE,” “CRUISE CTRL,” or similar. Fuses are typically 10A or 15A, but values vary by model.


• ECM/PCM or engine-management fuse: Powers the engine computer and may feed the cruise control module through the wiring harness.


• Relay that controls the cruise control module: Some vehicles use a separate relay in the fuse/relay box to feed the cruise control unit.

After inspecting these fuses, replace any that are blown with the same amperage rating. If the fuse continues to blow, there may be a short or fault in the cruise control wiring or module that requires professional diagnosis.

Other causes when the fuse is fine

If the fuse is intact, several other factors can prevent cruise control from working. These issues can be intermittent or prevent engagement, but they do not involve a blown fuse.

• Faulty brake switch or clutch switch: The cruise control system typically disengages when the brake is pressed or the clutch is depressed.


• Faulty or dirty vehicle speed sensor (VSS): The system relies on accurate speed data to maintain the set speed.


• Cruse control module or throttle actuator failure: The control unit or servo that regulates throttle can fail or become stuck.


• Wiring harness damage or poor connections: Corrosion, chafed wires, or loose connectors can interrupt signals.


• Software/ECU calibration or fault codes: An ECU fault can disable cruise control until repaired.

Diagnosing cruise control issues often involves scanning for fault codes, inspecting fuses, and testing the brake switch and speed sensor. If the issue persists after checking the fuse, consult a qualified mechanic or dealership for deeper diagnostics using OEM-level tools.

Summary

In short, a blown fuse can indeed stop cruise control from working by cutting power to the cruise control circuit. However, many other problems can mimic the symptom, including faulty sensors, switches, module failures, or wiring issues. Start with a fuse check, then broaden the diagnosis to related components, and seek professional help if the problem remains unresolved.

What would cause cruise control to stop working?

Cruise control often stops working due to a faulty brake switch or fuse, a bad cruise control switch on the steering wheel, or a problem with the speed sensor. Other potential issues include wiring problems, vacuum leaks in older systems, or issues with the vehicle's control module or check engine light. 
Common causes
This video explains 7 common reasons why your cruise control is not working: 55scar PROblemsYouTube · Aug 5, 2022

• Faulty brake switch: The cruise control system is disabled when you press the brake pedal. A faulty brake light switch can send an incorrect signal, or the brake lights may not work, which will prevent cruise control from engaging. A similar issue can occur with the clutch pedal switch in a manual transmission vehicle. 
• Blown fuse: A blown fuse is a common and simple cause for a complete loss of power to the cruise control system. 
• Problem with the cruise control switch: The switch on the steering wheel or stalk can wear out or have a loose connection, preventing it from sending a signal to the system. 
• Speed sensor issues: The vehicle's speed sensor provides data to the cruise control system. If the sensor is faulty or dirty, it may not provide accurate information, causing the system to malfunction. 
• Wiring and electrical issues: Damaged or disconnected wiring, including the spiral cable on the steering wheel, can disrupt the communication between the different parts of the cruise control system. 
• Vacuum leaks: In older vehicles, a vacuum-operated system can be disabled by a leak in the vacuum hoses or a problem with the vacuum actuator. 
• Other electronic issues: A malfunctioning control module (ECM or PCM), or other electronic throttle actuator problems, can also be the cause of the failure. 
• Obstructions for adaptive cruise control: For adaptive systems, a dirty or blocked camera or radar sensor from weather, dirt, or even direct sun glare can prevent it from working. 

What you can check

• Check brake lights: Ensure all your brake lights are working correctly. If not, a faulty brake light switch could be the cause. 
• Inspect the fuse: Locate the cruise control fuse in your owner's manual and check if it's blown. 
• Examine the cruise control switch: Press the buttons to see if the dashboard light for cruise control comes on. Also, check for any signs of wear or loose connections. 
• Look for check engine light: If the check engine light is on, it can disable cruise control to prevent damage to other components. 
• Check for obstructions (adaptive cruise control): Make sure the cameras or sensors on the windshield are clean and free of obstructions. 

If these basic checks don't resolve the issue, a professional mechanic can diagnose and fix more complex problems, such as issues with the control module or sensor replacements.

How do I know if my cruise control fuse is blown?

You can tell a cruise control fuse is blown by the cruise control system not working at all. To confirm, use a multimeter or a test light to check for continuity or power on both sides of the fuse. If the test light doesn't illuminate on one side when power is applied, or if the multimeter shows no continuity, the fuse is blown and needs to be replaced. 
This video demonstrates how to test a fuse with a multimeter: 54sBarbour's Auto HelpYouTube · Jul 16, 2019
How to check the fuse

1. Locate the fuse box: Consult your vehicle's owner's manual to find the correct fuse box and the location of the dedicated cruise control fuse. Fuses are typically in the dashboard or engine bay. 
2. Test with a test light: 
   • Turn the ignition key to the "On" position. 
   • Touch the probe of the test light to the back of one terminal on the fuse. 
   • If the light doesn't turn on, try the other terminal. 
   • If the light illuminates on both sides, the fuse is good. If it doesn't light up on one side, the fuse is blown. 
3. Test with a multimeter: 
   • Set the multimeter to the ohms (Ωcap omegaΩ) or continuity setting. 
   • Touch one probe to each end of the fuse. 
   • If the fuse is good, there should be continuity (the meter will show a reading close to zero or a "OL" will not appear). 
   • If there is no continuity, the fuse is blown. 
4. Replace the fuse: If the fuse is blown, replace it with a new one of the same amperage rating. 

This video explains the causes of cruise control not working, including blown fuse: 59sOBD InsightsYouTube · Mar 5, 2024

Can a blown fuse disable cruise control?

Blown Fuse
All electrical transmissions in a vehicle are enhanced and controlled by fuses. Once the engine control system detects a defect in the fuse and other electrical components, it sends a check engine warning light to the dashboard and eventually disables the cruise control system.

What is the most common failure of a cruise control system?

The most common failures of a cruise control system are due to a faulty brake light switch or a blown fuse, as these are essential safety interlocks and power sources for the system. Other common issues include problems with the speed sensor, the cruise control switch on the steering wheel, or the check engine light being illuminated.
 
Common cruise control failures

• Faulty brake light switch: The cruise control system is designed to disengage when the brake pedal is pressed. If the switch malfunctions, it may falsely report that the brake is being applied, preventing the system from working. 
• Blown fuse: Fuses protect the electrical components of the cruise control system. A blown fuse will cut power to the system, causing it to fail until the fuse is replaced. 
• Speed sensor issues: The system relies on accurate vehicle speed data from a speed sensor. If the sensor fails or provides incorrect information, the cruise control may not engage or may disengage unexpectedly. 
• Damaged switches: The physical switches on the steering wheel that activate the cruise control can wear out over time or become damaged from spills, preventing them from sending signals to the system. 
• Check engine light: If a problem with the engine is detected, the vehicle's computer will often automatically disable the cruise control system as a safety precaution. 

Other potential problems

• Spiral cable: The flexible cable connecting the steering wheel controls to the car's electrical system can become damaged. 
• Vacuum leaks: In older systems, leaks in the vacuum lines can cause the system to malfunction. 
• Electrical issues: Damaged wiring or faulty connectors can disrupt the system's operation.