2003 GMC Safari Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 2003 GMC Safari and How to Fix Them

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Reviewed by
Aisha
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 2003 GMC Safari 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 2003 GMC Safari 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.

When the throttle position sensor fails, the engine's computer tends to overcompensate with fuel, leading black exhaust coming from the tailpipe. There is a strong possibility of engine misfires, and the check engine light will come on.

Throttle position sensors can also develop "dead spots," or certain places along the throttle curve where it doesn't get a reading. When this happens, the above symptoms can occur but then stop when you further press or let off the gas pedal.

When the vehicle speed sensor fails or the wiring harness prevents signal transmission, the speedometer is the first thing that will stop functioning properly. This can be an intermittent issue where the speedometer only works occasionally, the speedometer may cease all function, or the speedometer may read erratically or incorrectly. Also, the traction control and anti lock brake warning lights specific to each vehicle may be illuminated, depending on the design of those systems. You may notice the vehicle hesitate to accelerate, cruise control will not function properly, and the vehicle may not shift properly through all of the gears.

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.

A faulty cruise control module will simply result in deactivation of cruise control settings. This is because a detected error in the cruise control system could lead to hazardous driving conditions, so the module will be disabled, and the cruise control system warning light will be displayed. This will be a different message depending on make and model, and a warning light or message may be displayed on the driver instrument cluster.

What are the steps to diagnose the non-functioning cruise control in a 2003 GMC Safari?

To effectively diagnose the non-functioning cruise control in a 2003 GMC Safari, start with a systematic approach that prioritizes simpler checks before moving on to more complex diagnostics. Begin by inspecting the fuse associated with the cruise control system, as a blown fuse is a common and easily fixable issue. Next, examine the cruise control switch located on the steering wheel; a malfunctioning switch can prevent the system from engaging. Following this, check the brake pedal switch, which is crucial since the cruise control disengages when the brake is applied. If these components are functioning correctly, turn your attention to the speed sensor, as it plays a vital role in relaying vehicle speed to the cruise control system. Additionally, inspect the vacuum lines for any leaks, as these can disrupt the operation of the cruise control. Finally, if the problem persists, utilize a diagnostic scanner to identify any error codes that may provide further insight into the underlying issue. By following this structured diagnostic approach, you can efficiently identify and resolve the problem with your cruise control system.

What are the common problems that could cause the cruise control to stop working in a 2003 GMC Safari?

When troubleshooting cruise control issues in a 2003 GMC Safari, it's essential to consider several common problems that could be affecting the system's performance. One of the first areas to check is the cruise control switch, as a faulty switch can prevent the system from engaging or disengaging properly. Additionally, inspect the vehicle's fuse box for any blown fuses, as this can disrupt the cruise control's functionality. Another critical aspect to examine is the vacuum system; vacuum leaks can lead to a loss of pressure, causing the cruise control to malfunction. The speed sensor also plays a vital role, and if it is defective, it may fail to maintain the desired speed accurately. Lastly, issues with the brake light switch can interfere with the cruise control's operation, as it is designed to disengage when the brakes are applied. By systematically checking these components, you can effectively diagnose and resolve the cruise control problems in your GMC Safari.

How urgent is it to address the non-functioning cruise control in a 2003 GMC Safari?

Addressing a non-functioning cruise control in a 2003 GMC Safari is important, even if it may not seem urgent at first glance. While the absence of this feature might not directly impair the vehicle's drivability, it can signal underlying electrical or sensor issues that could escalate into more significant problems if left unattended. The cruise control system is designed to enhance driving comfort and fuel efficiency, and its malfunction could lead to driver fatigue during long trips, increasing the risk of accidents. Moreover, neglecting this issue could result in further damage to the vehicle's systems, potentially leading to costly repairs down the line. Therefore, it is advisable to have the cruise control inspected and repaired by a qualified mechanic to ensure the vehicle remains safe and performs optimally. Taking prompt action not only restores the convenience of cruise control but also safeguards against potential safety hazards and maintains the overall integrity of the vehicle.

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