1991 GMC R1500 Suburban Radiator Fan Isn't Working

Fixing a Non-Functional Radiator Fan in 1991 GMC R1500 Suburban

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
34% chance it's the
Fan Motor or Clutch
0%
28% chance it's the
Fan Relay or Fuse
0%
23% chance it's the
Temp Sensor or Fan Control Module
0%
15% chance it's
Something else
The most common reasons a 1991 GMC R1500 Suburban radiator fan isn't working are the fan assembly, the fan clutch, or the coolant temperature sensor.
  • Fan Motor or Clutch: A faulty fan motor or a malfunctioning fan clutch can result in inadequate cooling, causing the engine to overheat.
  • Fan Relay or Fuse: A faulty fan relay or blown fuse can prevent the cooling fan from operating, leading to engine overheating.
  • Temp Sensor or Fan Control Module: A faulty temperature sensor or fan control module can result in incorrect readings, causing the engine to overheat or the cooling fan to operate improperly.
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 R1500 Suburban radiator fan 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.

Over time serpentine belts stretch, crack, and the ribs that ride on the accessory pulleys being to wear smooth. A squealing noise that increases with engine speed or as engine driven accessories are turned on may be noted. The noise is caused by the belt slipping on the pulleys, insufficiently driving them. Ineffective air conditioning, a battery warning light, or intermittent power steering assist can result from this.

»MORE: Symptoms of a bad serpentine belt

The first indication of a defective fan clutch is a healthy cooling system that runs below or above the normal temperature range. This is due to the fan running too fast or too slow. Also, a seized cooling fan will cause a loud roaring fan noise from under the hood every time the accelerator is pressed, and the engine will feel as if it lacks power. In this situation it would be very difficult to turn the engine cooling fan by hand, of course when the vehicle is off. Finally, if the clutch fails the fan will either turn very slowly, and not respond well to engine speed.

When the engine coolant temperature sensor fails, it will send inaccurate information to the vehicle’s computer, causing the computer to react to false operating conditions. This will cause the engine to consume more fuel than normal, depleting fuel mileage, and causing black, sooty smoke from the engine under moderate to heavy acceleration. The check engine light will illuminate, and on-board diagnostic trouble codes may be stored for exhaust and emission system failure, fuel delivery system failure, and engine cooling system failure. Overheating may also occur, as the coolant sensor may be leaking fluid out of the engine, creating a an air pocket in the system.

What steps should I take to diagnose the non-functioning radiator fan in my 1991 GMC R1500 Suburban?

To effectively diagnose the non-functioning radiator fan in your 1991 GMC R1500 Suburban, start with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Begin by inspecting the fuse associated with the radiator fan; a blown fuse is a common and easily fixable issue. If the fuse is intact, move on to examining the wiring harness for any signs of damage, such as fraying or corrosion, which could disrupt the electrical flow. Next, visually assess the fan itself for any physical damage, including broken blades or a burned-out motor, as these can directly impact functionality. If the fan appears intact, conduct a test to ensure it operates correctly, as this will help you determine if the problem lies within the fan or elsewhere in the system. Additionally, check for any obstructions that may be blocking the fan blades, as these can prevent proper movement. Lastly, inspect the starter relay, as a malfunction here can also lead to the fan not turning on. By following this structured diagnostic approach, you can efficiently identify the root cause of the issue and take the necessary steps to restore your radiator fan's functionality.

What are the common causes for the radiator fan not working in a 1991 GMC R1500 Suburban?

When troubleshooting the radiator fan in a 1991 GMC R1500 Suburban, it's essential to consider several common problems that could be causing the fan to malfunction. One of the primary culprits is a faulty fan motor, which can prevent the fan from operating effectively. Additionally, a blown fuse in the fuse box may disrupt the electrical flow to the fan, so checking for any damaged fuses is a crucial step. Another potential issue is a defective relay that controls the fan's operation; if this relay fails, the fan won't turn on as needed. Furthermore, the coolant temperature sensor plays a vital role in activating the fan when the engine reaches a certain temperature, and if this sensor is malfunctioning, it may need replacement. Wiring issues, such as damaged or disconnected wires, can also hinder the fan's performance, making it important to inspect the electrical connections. Lastly, problems within the cooling system itself, like low coolant levels or a malfunctioning water pump, can indirectly affect the fan's operation. By systematically checking these areas, you can effectively diagnose and resolve the issue of a non-working radiator fan in your Suburban.

How urgent is it to repair the non-functioning radiator fan in a 1991 GMC R1500 Suburban?

When it comes to the radiator fan in your 1991 GMC R1500 Suburban, addressing a malfunction promptly is not just a matter of convenience; it’s a critical safety concern. The radiator fan is essential for maintaining optimal engine temperatures by effectively dissipating heat. If the fan fails, the engine is at risk of overheating, which can lead to severe damage such as warped components or a blown head gasket. These issues not only result in costly repairs but can also leave you stranded, posing a significant safety hazard. Moreover, an overheating engine can diminish your vehicle's performance and fuel efficiency, making it imperative to act quickly. By prioritizing the repair of your radiator fan, you safeguard your engine's health and ensure a safer driving experience, making it a crucial DIY task that should not be overlooked.

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Troubleshooting 1991 GMC R1500 Radiator Fan Problems