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Home >> Pontiac >> 2006 >> Vibe Base, AWD >> Repair and Diagnosis (Single Page) >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> Cooling Fan Inoperative (Low Speed Operates in High Speed)

Cooling Fan Inoperative (Low Speed Operates in High Speed)

Reference Table

Symptom Causes
Fan motor inoperative in both speeds
  • Open or short to ground in the fan 1 relay supply voltage circuits.
  • Open or short to B+ in the fan 1 relay coil control circuit.
  • Open or short to ground in the fan motor supply voltage circuit.
  • Short to ground in the fan 2 coil supply voltage circuit.
  • Open or short to B+ in the fan motor ground circuit.
  • Short to B+ in the fan 2 coil control circuit.
Fan motor inoperative in high speed only
  • Open in the fan 2 relay supply voltage circuit.
  • Open in the fan 2 relay coil control circuit.
  • Open in the fan 2 relay high speed ground circuit.
Fan motor low speed operates at high speed
  • Short to ground in the fan motor ground circuit.
  • Short to ground in the fan resistor circuit.
Fan motor inoperative in low speed only Open or short to B+ in the fan resistor circuit.
Cooling Fan Inoperative (Low Speed Operates in High Speed)

Step Action Yes No
Schematic Reference: Engine Cooling Schematics .
Connector End View Reference: Cooling System Connector End Views 
DEFINITION: The cooling fan motor low speed operates at high 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. Connect a scan tool. The engine must be below operating temperature.
  2. Use the scan tool to command the A/C compressor clutch relay ON. When the relay is energized the cooling fan will also run at low speed.
Does the cooling fan operate at high speed?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3
  1. Remove the fan 2 relay.
  2. Use the scan tool to command the cooling fan ON.
Does the cooling fan operate at high speed?
Go to Step 8  Go to Step 4 
4 Test the fan 2 relay. The relay should be normally open between terminals 3 and 5 and normally closed between terminals 3 and 4.
Did the relay test OK?
Go to Step 5  Go to Step 9 
5 Test the fan 2 relay coil control circuits 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 12  Go to Step 6 
6 Test the refrigerant pressure switch for a closed condition. The switch should be normally open between terminals 2 and 3.
Did the switch test OK?
Go to Step 7  Go to Step 10 
7 Inspect for a poor connection at the harness connector of the Powertrain Control Module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 12  Go to Step 11 
8 Repair the short to ground in the fan motor ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?
Go to Step 12  -
9 Replace the fan 2 relay. Refer to Cooling Fan Relay Replacement .
Did you complete the replacement?
Go to Step 12  -
10 Replace the refrigerant pressure switch. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating,Ventilation and Air Conditioning.
Did you complete the replacement?
Go to Step 12  -
11 Replace the PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup.
Did you complete the replacement?
Go to Step 12  -
12 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 3