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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1377 (Engine Cooling System) >> Diagnostic Information and Procedures >> Cooling Fan Always On (Always On in Low Speed)

Cooling Fan Always On (Always On in Low Speed)

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
Reference Table

Symptom Causes
Fan motor always on in high speed Short to ground in the fan 2 relay coil control circuits.
Fan motor always on in low speed
  • Short to ground in the fan 1 relay coil control circuit.
  • Short to B+ in the fan motor supply voltage circuit.
Cooling Fan Always On (Always On in Low Speed)

Step Action Yes No
Schematic Reference: Engine Cooling Schematics 
Connector End View Reference: Cooling System Connector End Views 
DEFINITION: The cooling fan motor is always on in low speed.
1 Did you review the Cooling System Description and Operation  and perform the necessary inspections? Go to Step 2  Go to Symptoms - Engine Cooling 
2
  1. Ensure that the ECT is below 93° C (199° F).
  2. Depress the A/C switch to the OFF position.
  3. Turn the blower switch to the OFF position.
  4. Turn the ignition switch to the RUN position.
Is the fan motor running continuously?
Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3 Remove the fan 1 relay from the underhood fuse block.
Is the fan motor running continuously?
Go to Step 4  Go to Step 5 
4 Repair the short to voltage in the fan motor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 7  -
5 Test the fan 1 relay coil control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 7  Go to Step 6 
6 Replace the fan 1 relay. Refer to Cooling Fan Relay Replacement .
Did you complete the replacement?
Go to Step 7  -
7 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 3