1990 GMC K3500 Cruise Control Isn't Working

Fixing Cruise Control Issues in Your 1990 GMC K3500

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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 1990 GMC K3500 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 1990 GMC K3500 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.

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 1990 GMC K3500?

When diagnosing the non-functioning cruise control in a 1990 GMC K3500, it's crucial to adopt a systematic diagnostic approach that begins with the most straightforward solutions. Start by checking the fuse associated with the cruise control system, as a blown fuse is a common and easily fixable issue. Next, inspect the cruise control switch to ensure it is operational; a malfunctioning switch can prevent the system from engaging. Given the age of the vehicle, examining the vacuum lines is also essential, as any leaks or damage can disrupt the cruise control's functionality. Following these checks, test the cruise control module to confirm it is working correctly, and ensure the speed sensor is providing accurate readings, as it plays a vital role in the system's operation. If these initial steps do not resolve the issue, seeking assistance from a professional mechanic with experience in older vehicles may be necessary. By following this structured approach, you can effectively diagnose and potentially resolve the cruise control issue in your GMC K3500.

What are the common problems that could cause the cruise control to stop working in a 1990 GMC K3500?

When troubleshooting cruise control issues in a 1990 GMC K3500, it's essential to understand the common problems that may arise. One frequent culprit is the failure of control modules or switches, particularly the brake and clutch switches, which can disrupt the system's operation. Additionally, broken wires connected to these switches can lead to intermittent or complete failure of the cruise control. Another area to inspect is the fuses; a blown fuse can prevent the cruise control from functioning altogether. The brake pedal switch is also critical, as a defect here can signal the system to disengage unexpectedly. Lastly, issues with the throttle can affect the cruise control's ability to maintain speed. By systematically checking these components, DIYers can often identify and resolve the issues, restoring the cruise control functionality in their GMC K3500.

How urgent is it to repair the non-functioning cruise control on a 1990 GMC K3500?

When contemplating the urgency of repairing the non-functioning cruise control on your 1990 GMC K3500, it's essential to weigh the implications of neglecting this issue. While cruise control is primarily a convenience feature, its malfunction can lead to safety concerns, especially during long drives where driver fatigue is a factor. If the system's failure affects your ability to maintain control or focus, it becomes more critical to address the repair promptly. Additionally, if you rely on cruise control for a more comfortable driving experience, the inconvenience of its absence may warrant a quicker resolution. Furthermore, from a resale perspective, a fully functional cruise control system can enhance your vehicle's appeal and value, making it a worthwhile investment to repair sooner rather than later. Ultimately, the decision hinges on your personal driving habits and priorities, but considering the potential safety risks and the impact on comfort and resale value can guide you in determining the urgency of the repair.

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