Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: The engine cooling fan motor does not operate.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Ignition ON, A/C OFF, if equipped. Engine temperature below 93°C (200°F). Observe that the fan is OFF.
2. Disconnect the engine coolant temperature (ECT) sensor connector. Observe that the fan activates.

Was the fan OFF and then ON?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

1. Turn OFF the ignition.
2. Remove the cooling fan relay.
3. Probe the battery positive voltage circuit of the cooling fan relay switch side with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 7

Connect a 20-amp fused jumper wire between the battery positive voltage circuit of the cooling fan relay and the cooling fan motor supply voltage circuit of the cooling fan relay.

Does the cooling fan operate?

Go to Step 10

Go to Step 5

1. Disconnect the cooling fan connector.
2. Probe the cooling fan motor supply voltage circuit at the harness connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

Probe the harness connector of the cooling fan motor with a test lamp connected between the cooling fan motor supply voltage circuit and the ground circuit of the cooling fan motor.

Does the test lamp illuminate?

Go to Step 11

Go to Step 9

Repair the battery positive circuit of the cooling fan relay. Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 14

--

Repair the supply voltage circuit of the cooling fan motor. Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 14

--

Repair the ground circuit of the cooling fan motor. Refer to Circuit Testing and Wiring Repairs.

Did you complete the repair?

Go to Step 14

--

Inspect for poor connections at the cooling fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

Inspect for poor connections at the harness connector of the cooling fan motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

Replace the cooling fan relay.

Did you complete the repair?

Go to Step 14

--

Replace the cooling fan motor. Refer to Cooling Fan and Shroud Replacement.

Did you complete the repair?

Go to Step 14

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: One or both cooling fan motors are inoperative in either high, low, or both speeds.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Install a scan tool.
2. Turn ON the engine.
3. With a scan tool, monitor the engine coolant temperature (ECT) in the Inputs/Outputs scan tool data.
4. Bring the vehicle up to normal operating temperature.
5. At 106°C (223°F) the low speed engine cooling fans should engage.

Do the low speed engine cooling fans engage?

Go to Step 3

Go to Step 4

Important:: A 3 second delay occurs before the powertrain control module (PCM) changes the cooling fan speed.

1. With a scan tool, monitor the ECT in the Inputs/Outputs scan tool data.
2. At 110°C (230°F) the high speed engine cooling fans should engage.

Do the high speed engine cooling fans engage?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 6

Important: Do NOT remove the jumper wire that you will be connecting until your testing is completed. If the cool fan 1 fuse opens when you connect the jumper wire, repair the cooling fan motor supply voltage circuit of the left cooling fan motor for a short to ground.

1. Disconnect the cool fan 1 relay.
2. Connect a jumper wire between the battery positive voltage circuit and the cooling fan motor supply voltage circuit of the cool fan 1 relay.

Do both cooling fans operate in low speed?

Go to Step 14

Go to Step 5

1. Disconnect the S/P fan relay.
2. With a test lamp connected to a good ground, probe the cooling fan low reference circuit at the S/P fan relay.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

Does the left cooling fan operate at high speed?

Go to Step 16

Go to Step 7

Inspect the ground circuit of the S/P fan relay for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 15

1. Install the S/P fan relay.
2. Disconnect the left cooling fan electrical connector.
3. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the left cooling fan motor connector.

Does the test lamp illuminate?

Go to Step 12

Go to Step 13

1. Install the S/P fan relay.
2. Disconnect the right cooling fan motor connector.
3. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the right cooling fan connector.

Does the test lamp illuminate?

Go to Step 11

Go to Step 10

Inspect the cooling fan motor supply voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 15

Inspect the ground circuit of the right cooling fan for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 18

Inspect the cooling fan low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 17

Inspect the cooling fan motor supply voltage circuit of the left cooling fan for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 19

Inspect for poor connections at the cool fan 1 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 20

Inspect for poor connections at the S/P fan relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 21

Inspect for poor connections at the cool fan 2 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 22

Inspect for poor connections at the harness connector of the left cooling fan. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 23

Inspect for poor connections at the harness connector of the right cooling fan. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 25

Go to Step 24

Repair the battery positive voltage circuit for an open or high resistance. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 25

--

Replace the cool fan 1 relay.

Did you complete the replacement?

Go to Step 25

--

Replace the S/P fan relay.

Did you complete the replacement?

Go to Step 25

--

Replace the cool fan 2 relay.

Did you complete the replacement?

Go to Step 25

--

Replace the left cooling fan. Refer to Cooling Fan and Shroud Replacement .

Did you complete the replacement?

Go to Step 25

--

Replace the right cooling fan. Refer to Cooling Fan and Shroud Replacement .

Did you complete the replacement?

Go to Step 25

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: One or both cooling fan motors are inoperative in either high, low, or both speeds.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Install a scan tool.
2. Turn ON the engine.
3. With a scan tool, monitor the engine coolant temperature (ECT) in the Inputs/Outputs scan tool data.
4. Bring the vehicle up to normal operating temperature.
5. At 106°C (223°F) the low speed engine cooling fans should engage.

Do the low speed engine cooling fans engage?

Go to Step 3

Go to Step 4

Important:: A 3 second delay occurs before the powertrain control module (ECM) changes the cooling fan speed.

1. With a scan tool, monitor the ECT in the Inputs/Outputs scan tool data.
2. At 110°C (230°F) the high speed engine cooling fans should engage.

Do the high speed engine cooling fans engage?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 6

Important: Do NOT remove the jumper wire that you will be connecting until your testing is completed. If the cool fan 1 fuse opens when you connect the jumper wire, repair the cooling fan motor supply voltage circuit of the left cooling fan motor for a short to ground.

1. Disconnect the cool fan 1 relay.
2. Connect a jumper wire between the battery positive voltage circuit and the cooling fan motor supply voltage circuit of the cool fan 1 relay.

Do both cooling fans operate in low speed?

Go to Step 12

Go to Step 5

With a test lamp connected to good ground, probe the cooling fan low reference or ground circuit at the dual speed cooling fan motor.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

Does the dual speed cooling fan operate at high speed?

Go to Step 13

Go to Step 7

1. Disconnect the low speed circuit of the dual speed cooling fan motor connector.
2. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the low speed cooling fan connector.

Does the test lamp illuminate?

Go to Step 10

Go to Step 9

1. Disconnect the high speed circuit of the dual speed cooling fan motor connector.
2. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the high speed cooling fan connector.

Does the test lamp illuminate?

Go to Step 10

Go to Step 9

Inspect the appropriate cooling fan motor supply voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 15

Inspect the dual speed cooling fan low reference or ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 16

Inspect for poor connections at the cool fan 1 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 16

Inspect for poor connections at the cool fan 2 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 17

Inspect for poor connections at the harness connector of the low speed cooling fan circuit at the cooling fan motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 18

Inspect for poor connections at the harness connector of the high speed cooling fan circuit of the cooling fan motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 18

Replace the cool fan 1 relay.

Did you complete the replacement?

Go to Step 19

--

Replace the cool fan 2 relay.

Did you complete the replacement?

Go to Step 19

--

Replace the dual speed cooling fan motor. Refer to dual speed cooling fan replacement.

Did you complete the replacement?

Go to Step 19

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3