Schematic Reference: Engine Cooling Schematics

DEFINITION: One or both engine cooling fan motors do not operate properly in high or low speed modes.

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, command the Fans Low Speed ON and OFF.

Do the low speed engine cooling fans turn ON and OFF with each command?

Go to Step 3

Go to Step 4

Important:: Before the PCM changes the speed of the cooling fans, a 3-second delay occurs.

With a scan tool, command the Fans High Speed ON and OFF.

Do the high speed engine cooling fans turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 11

Important: Following this step, do not remove the 20-A fused jumper wire that is connected during this step. While performing the following steps, use a second 20-A fused jumper wire.

1. Disconnect the cool fan 1 relay.
2. Connect a 20-A fused jumper between the battery positive voltage circuit of the cool fan 1 relay 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 13

Go to Step 5

1. Disconnect the cool fan relay.
2. Connect the second 20-A fused jumper between the right cooling fan low reference circuit of the cool fan relay and the left cooling fan motor supply voltage circuit of the cool fan relay.

Do both cooling fans operate in low speed?

Go to Step 14

Go to Step 6

Connect the second 20-A fused jumper between the battery positive voltage circuit of the cool fan relay and the cooling fan motor supply voltage circuit of the cool fan relay.

Does the left cooling fan operate in high speed?

Go to Step 9

Go to Step 7

1. Install the cool fan relay.
2. Disconnect the left cooling fan electrical connector.
3. Connect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the left cooling fan electrical connector to the cooling fan ground circuit of the left cooling fan electrical connector.

Does the right cooling fan operate in high speed?

Go to Step 16

Go to Step 8

Connect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the left cooling fan electrical connector to a good ground.

Does the right cooling fan operate in high speed?

Go to Step 20

Go to Step 21

1. Install the cool fan relay.
2. Disconnect the right cooling fan electrical connector.
3. Connect the second 20-Amp fused jumper wire from the motor supply voltage circuit of the right cooling fan electrical connector to the low reference circuit of the right cooling fan electrical connector.

Does the left cooling fan operate in high speed?

Go to Step 17

Go to Step 10

Connect the second 20-Amp fused jumper wire from battery positive voltage to the right cooling fan low reference circuit of the of the right cooling fan electrical connector.

Does the left cooling fan operate in high speed?

Go to Step 18

Go to Step 22

Is the left cooling fan operating properly in high speed?

Go to Step 12

Go to Step 15

1. Disconnect the cool fan relay.
2. Connect the second 20-A fused jumper between the right cooling fan low reference circuit of the cool fan relay and the ground circuit of the cool fan relay.

Does the right cooling fan operate properly in high speed?

Go to Step 14

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 23

Inspect for poor connections at the cool fan relay. 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 28

Go to Step 24

Inspect for poor connections at the cool fan 2 relay. 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 28

Go to Step 25

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 26

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 27

Repair the right cooling fan supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the right cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the left cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the left cooling fan supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the right cooling fan low reference circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Replace the cool fan 1 relay.

Is the repair complete?

Go to Step 28

--

Replace the cool fan relay.

Is the repair complete?

Go to Step 28

--

Replace the cool fan 2 relay.

Is the repair complete?

Go to Step 28

--

Replace the left cooling fan. Refer to Engine Coolant Fan Motor Replacement .

Is the repair complete?

Go to Step 28

--

Replace the right cooling fan. Refer to Engine Coolant Fan Motor Replacement .

Is the repair complete?

Go to Step 28

--

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

DEFINITION: One or both engine cooling fan motors do not operate properly in high or low speed modes.

1

Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, command the Fans Low Speed ON and OFF.

Do the low speed engine cooling fans turn ON and OFF with each command?

Go to Step 3

Go to Step 4

Important:: Before the PCM changes the speed of the cooling fans, a 3-second delay occurs.

With a scan tool, command the Fans High Speed ON and OFF.

Do the high speed engine cooling fans turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 11

Important: Following this step, do not remove the 20-A fused jumper wire that is connected during this step. While performing the following steps, use a second 20-A fused jumper wire.

1. Disconnect the Cool Fan 1 relay.
2. Connect a 20-A fused jumper between the battery positive voltage circuit of the cool fan 1 relay 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 13

Go to Step 5

1. Disconnect the cool fan relay
2. Connect the second 20-A fused jumper between the left cooling fan low reference circuit of the cool fan relay and the right cooling fan supply voltage circuit of the cool fan relay.

Do both cooling fans operate in low speed?

Go to Step 14

Go to Step 6

Connect the second 20-A fused jumper between the battery positive voltage circuit of the cool fan relay and the cooling fan motor supply voltage circuit of the cool fan relay.

Does the right cooling fan operate in high speed?

Go to Step 9

Go to Step 7

1. Install the cool fan relay.
2. Disconnect the right cooling fan electrical connector.
3. Connect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to the cooling fan ground circuit of the right cooling fan electrical connector.

Does the left cooling fan operate in high speed?

Go to Step 16

Go to Step 8

Connect the second 20-Amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to a good ground.

Does the left cooling fan operate in high speed?

Go to Step 20

Go to Step 21

1. Install the cool fan relay.
2. Disconnect the left cooling fan electrical connector.
3. Connect the second 20-Amp fused jumper wire from the motor supply voltage circuit of the left cooling fan electrical connector to the low reference circuit of the left cooling fan electrical connector.

Does the right cooling fan operate in high speed?

Go to Step 17

Go to Step 10

Connect the second 20-Amp fused jumper wire from battery positive voltage to the left cooling fan low reference circuit of the of the left cooling fan electrical connector.

Does the right cooling fan operate in high speed?

Go to Step 18

Go to Step 22

Is the right cooling fan operating properly in high speed?

Go to Step 12

Go to Step 15

1. Disconnect the cool fan relay.
2. Connect the second 20-A fused jumper between the right cooling fan low reference circuit of the cool fan relay and the ground circuit of the cool fan relay.

Does the left cooling fan operate properly in high speed?

Go to Step 14

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 23

Inspect for poor connections at the cool fan relay. 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 28

Go to Step 24

Inspect for poor connections at the cool fan 2 relay. 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 28

Go to Step 25

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 26

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 28

Go to Step 27

Repair the left cooling fan supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the left cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the right cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the right cooling fan motor supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Repair the left cooling fan low reference circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 28

--

Replace the cool fan 1 relay.

Is the repair complete?

Go to Step 28

--

Replace the cool fan relay.

Is the repair complete?

Go to Step 28

--

Replace the cool fan 2 relay.

Is the repair complete?

Go to Step 28

--

Replace the right cooling fan. Refer to Engine Coolant Fan Motor Replacement .

Is the repair complete?

Go to Step 28

--

Replace the left cooling fan. Refer to Engine Coolant Fan Motor Replacement .

Is the repair complete?

Go to Step 28

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3