1991 GMC G2500 Cruise Control Isn't Working

Fixing cruise control issues in the 1991 GMC G2500

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Reviewed by
Devin Cabugcal
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 1991 GMC G2500 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 1991 GMC G2500 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 initial steps to diagnose the non-functioning cruise control in a 1991 GMC G2500?

When diagnosing the non-functioning cruise control in a 1991 GMC G2500, it's essential to adopt a systematic approach that prioritizes simpler checks before delving into more complex issues. Start by inspecting the fuse, as a blown fuse is a common and easily fixable problem that can prevent the cruise control from operating. Next, examine the cruise control module, as a malfunction here can lead to similar issues. It's also crucial to verify the brake switch, since a faulty switch can interrupt the cruise control system. Ensure that the ignition is on during your tests, as this is necessary for the system to function. Additionally, check the throttle cable to confirm it is operating correctly, as any restrictions can hinder engagement. Finally, look for any visible damage to the cruise control components, as physical wear or damage can also be a significant factor. By following this diagnostic approach, you can effectively identify and address the root cause of the cruise control malfunction in your vehicle.

What are the common problems that could cause the cruise control to stop working in a 1991 GMC G2500?

When troubleshooting the cruise control system in a 1991 GMC G2500, it's essential to consider several common issues that may be at play. One frequent culprit is the control module, which can fail and disrupt the entire system. Additionally, problems with the throttle actuation can prevent the cruise control from engaging properly. It's also important to inspect the brake and clutch switches, as these components often malfunction or have broken wires that can interrupt the cruise control function. A faulty cruise control switch itself may hinder activation, while a blown fuse or issues with the brake light can also be significant factors. Furthermore, the park/neutral position switch can affect the system's operation if it indicates an incorrect gear. Lastly, don't overlook the possibility of stored error codes or engine-related issues, as these can also impact the cruise control's performance. By systematically checking these components, DIYers can effectively diagnose and potentially resolve the cruise control issues in their GMC G2500.

How urgent is it to repair the non-functioning cruise control in a 1991 GMC G2500 to ensure safety on the road?

Repairing the non-functioning cruise control in a 1991 GMC G2500 should be considered a priority for any DIY enthusiast concerned about road safety. While it may not seem like an immediate emergency, the implications of a malfunctioning cruise control system can be significant. A properly functioning cruise control helps maintain a steady speed, which is crucial for reducing driver fatigue during long journeys. Conversely, if the system is faulty, it can lead to erratic acceleration or deceleration, creating dangerous driving conditions that could result in accidents. Additionally, in older vehicles, such as the GMC G2500, issues with the cruise control may signal deeper electrical problems that could compromise the vehicle's overall safety. Therefore, addressing this repair promptly not only enhances your driving experience but also safeguards both the driver and other road users from potential hazards. Taking the time to fix the cruise control system is a responsible step towards ensuring a safer journey on the road.

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1991 GMC G2500 Cruise Control Issues & Repair Costs