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Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers in the diagnostic table.

  1. 2:  There should be no binding or increased resistance as the cooling fan clutch is rotated.
  2. 4:  The cooling fan noise should increase as the cooling fan clutch engages. It can take up to 2 minutes for full cooling fan clutch engagement. If cooling fan clutch is previously fully engaged, then there will not be a noticeable change in cooling fan noise. Compare noise to a known good vehicle. If fan noise is louder than the known good vehicle, then answer Yes.
  3. 5:  In the previous step the cooling fan clutch was fully engaged. This step tests to ensure that the cooling fan clutch will disengage. A noticeable noise difference should be heard between a fully engaged cooling fan clutch and a disengaged cooling fan. The cooling fan clutch is completely disengaged when the excessive fan noise is not heard.
  4. 6:  This step clears DTC that were set during previous steps. Test driving the vehicle will attempt to set DTC not previous found in the Engine Cooling Diagnostic Check. If no DTC is set the condition is normal operation of the cooling fan.
Excessive Fan Noise

Step Action Yes No
Schematic Reference:  Engine Cooling Schematics  
Connector End View Reference:  Cooling System Connector End Views  
DEFINITION: The cooling fan clutch has excessive fan noise.
1 Did you perform the Engine Cooling Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Engine Cooling 
2  Rotate the cooling fan 3 complete revolutions?
Is the resistance of the cooling fan clutch even through out each rotation?		 Go to Step 4  Go to Step 3 
3 Inspect the cooling fan clutch for proper installation. Refer to Fan Clutch Replacement .
Did you find and correct the condition?		 Go to Step 9  Go to Step 7 
4 
IMPORTANT: DTC P1482, for 4.2L (LL8), and P0480, for 5.3L (LM4), will set when the cooling fan relay is disconnected.
  1. Turn OFF the ignition.
  2. Disconnect the coolant fan relay.
  3. Connect a 10-amp fused jumper wire between the cooling fan clutch supply voltage circuit of the cooling fan and the ignition 3 voltage circuit of the cooling fan relay.
  4. Start the engine.
  5. Raise engine speed to 2,000 RPM for 2 minutes.
Does the cooling fan clutch engage?		 Go to Step 5  Go to Step 7 
5 
IMPORTANT: Continuous excessive fan noise is due to a mechanical failure. If the fan noise decreases during this step, then there is an electrical malfunction. Replacing the cooling fan clutch will not correct the condition.
  1. Turn OFF the ignition.
  2. Remove the 10-amp fused jumper wire.
  3. Install cooling fan relay.
  4. Disconnect the cooling fan clutch connector.
  5. Start the engine.
  6. Raise engine speed to 2,000 RPM for 2 minutes.
Does the cooling fan disengage?		 System OK Go to Step 6 
6 
  1. Turn OFF the ignition.
  2. Connect the cooling fan clutch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, clear all DTC.
  5. Start the engine.
  6. Test drive vehicle.
  7. With a scan tool, observe the DTC list.
Does the scan tool display any cooling system DTC?		 Go to Diagnostic Trouble Code (DTC) List  System OK
7 Inspect for poor connections at the harness connector of the cooling fan clutch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 9  Go to Step 8 
8 Replace the cooling fan clutch. Refer to Fan Clutch Replacement .
Did you complete the replacement?		 Go to Step 9  -
9 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 3 
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