1995 Mercedes-Benz S420 Cruise Control Isn't Working

Fixing cruise control issues in the 1995 Mercedes-Benz S420

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
0%
25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 1995 Mercedes-Benz S420 cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty or malfunctioning sensor can lead to incorrect readings, causing issues with engine performance or other systems relying on accurate data.
  • Control Module: A faulty control module can lead to erratic vehicle behavior or failure of various electronic systems due to improper signal processing.
  • Throttle: A faulty throttle body or a defective accelerator pedal position sensor may be causing inconsistent throttle response.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 1995 Mercedes-Benz S420 cruise control isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

In the event that a wheel speed sensor fails, the ABS, traction control system (TCS) and manufacturer specific stability control system lights will illuminate, informing the driver that the systems are disabled. The vehicle will be more prone to tire slip, and normal driving patterns may need to be adjusted to correct for the loss of computer control. On older vehicle's, the speedometer can be affected, causing illumination of the check engine light as well.

What are the initial diagnostic steps to troubleshoot the non-functional cruise control in a 1995 Mercedes-Benz S420?

When troubleshooting the non-functional cruise control in a 1995 Mercedes-Benz S420, it's essential to adopt a methodical diagnostic approach. Start by checking the fuse box for any blown fuses related to the cruise control system, as this is a straightforward fix that can often resolve the issue. Next, inspect the cruise control switch located on the steering wheel to ensure it is operational; a malfunctioning switch can prevent the system from engaging. Following this, examine the cruise control module for any signs of damage or malfunction, as this component is crucial for the system's functionality. Additionally, inspect the vacuum lines connected to the cruise control system for leaks or damage, as these can significantly impact performance. It's also important to test the brake pedal switch, as a faulty switch can inadvertently disable the cruise control. Finally, verify the vehicle speed sensor to ensure it is accurately relaying speed information to the cruise control system. By systematically addressing these areas, you can effectively diagnose and potentially resolve the issues affecting your cruise control system.

What are the common problems that could cause the cruise control to stop working in a 1995 Mercedes-Benz S420?

When the cruise control in a 1995 Mercedes-Benz S420 ceases to function, several common problems may be at play. One of the primary culprits could be a failed control module, which is essential for the cruise control system's operation. Additionally, issues with sensors or switches can disrupt the system's functionality, leading to a complete failure. Throttle actuation problems are another frequent cause, as they can prevent the system from maintaining the desired speed. It's also important to check for a blown fuse or a defective brake pedal switch, as these components are critical for the cruise control to engage and disengage properly. Furthermore, a faulty brake light or a malfunctioning brake switch can send incorrect signals to the cruise control system, causing it to stop working. Lastly, if the check engine light is illuminated, it may indicate underlying engine-related issues that could affect the cruise control's performance. For those looking to diagnose and repair these issues themselves, a thorough inspection of these components is essential to restore the cruise control functionality.

How urgent is it to repair the non-functioning cruise control in a 1995 Mercedes-Benz S420?

When evaluating the urgency of repairing the non-functioning cruise control in a 1995 Mercedes-Benz S420, it's essential to understand that while this feature enhances driving comfort, its failure does not pose an immediate safety risk. Unlike critical systems such as brakes or steering, a malfunctioning cruise control primarily affects convenience, particularly during long highway drives. Therefore, while it is advisable to address the issue to improve your driving experience, it is not an urgent repair. Scheduling the inspection and repair of the cruise control system at your convenience will ensure that you can enjoy a more comfortable ride without compromising the vehicle's basic functionality or safety. This approach allows you to prioritize repairs based on your driving habits and needs, ensuring that your vehicle remains enjoyable and efficient for long-distance travel.

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