Schematic Reference: Engine Cooling Schematics

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

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 will occur.

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 13

1. Turn the ignition OFF.
2. Disconnect the cooling fan 1 relay.
3. Turn the ignition ON, with the engine OFF.
4. Probe the battery positive voltage circuit of the cooling fan 1 relay switch side with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 20

Connect a 20 A fused jumper between the battery positive voltage circuit of the cooling fan 1 relay and the cooling fan motor supply voltage circuit of the cooling fan 1 relay.

Do both cooling fans operate in low speed?

Go to Step 15

Go to Step 6

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Remove the cooling fan S/P relay
3. Connect a 20 A fused jumper between the eng cool LH fan low circuit of the cooling fan S/P relay and the eng cool RH fan supply voltage circuit of the cooling fan S/P relay.

Do both cooling fans operate in low speed?

Go to Step 16

Go to Step 7

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Connect a 20 A fused jumper between the battery positive voltage circuit of the cooling fan S/P relay and the cooling fan motor supply voltage circuit of the cooling fan S/P relay.

Does the eng cool RH fan operate in high speed?

Go to Step 11

Go to Step 8

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Install the cooling fan S/P relay.
3. Disconnect the eng cool RH fan electrical connector.

Does the eng cool LH fan operate in high speed?

Go to Step 24

Go to Step 9

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Connect a 20 Amp fused jumper wire from the cooling fan motor supply voltage circuit of the eng cool RH fan electrical connector to the cooling fan motor ground circuit of the eng cool RH fan electrical connector.

Does the eng cool LH fan operate in high speed?

Go to Step 18

Go to Step 10

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Connect a 20 Amp fused jumper wire from the cooling fan motor supply voltage circuit of the eng cool RH fan electrical connector to a good ground.

Does the eng cool LH fan operate in high speed?

Go to Step 23

Go to Step 24

1. Leave the fused jumper wire in the cooling fan 1 relay.
2. Install the cooling fan S/P relay.
3. Disconnect the eng cool LH fan electrical connector.
4. Connect a 20 Amp fused jumper wire from battery positive voltage circuit of the eng cool LH fan electrical connector to the cooling fan motor ground circuit of the eng cool LH fan electrical connector.

Does the eng cool RH fan operate in high speed?

Go to Step 19

Go to Step 12

1. Leave the fused jumper wire in place of the cooling fan 1 relay.
2. Connect a 20 Amp fused jumper wire from battery positive voltage to the eng cool LH fan low circuit of the of the eng cool LH fan electrical connector.

Does the eng cool RH fan operate in high speed?

Go to Step 21

Go to Step 25

Is the eng cool RH fan operating properly in high speed?

Go to Step 14

Go to Step 17

1. Remove the cooling fan S/P relay
2. Connect a 20 A fused jumper between the eng cool LH fan low circuit of the cooling fan S/P relay and the ground circuit of the cooling fan S/P relay.

Does the eng cool LH fan operate properly in high speed?

Go to Step 16

Go to Step 22

Inspect for poor connections at the cooling 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 31

Go to Step 26

Inspect for poor connections at the cooling fan S/P 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 31

Go to Step 27

Inspect for poor connections at the cooling 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 31

Go to Step 28

Inspect for poor connections at the harness connector of the eng cool RH 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 31

Go to Step 29

Inspect for poor connections at the harness connector of the eng cool LH 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 31

Go to Step 30

Repair the battery positive voltage circuit of the cooling fan 1 relay switch side. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Repair the eng cool LH fan supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Repair the eng cool LH fan ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Repair the eng cool RH fan ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Repair the eng cool RH fan supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Repair the eng cool LH fan low circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 31

--

Replace the cooling fan 1 relay.

Did you complete the repair?

Go to Step 31

--

Replace the cooling fan S/P relay.

Did you complete the repair?

Go to Step 31

--

Replace the cooling fan 2 relay.

Did you complete the repair?

Go to Step 31

--

Replace the eng cool RH fan. Refer to Engine Cooling Fan Replacement .

Did you complete the repair?

Go to Step 31

--

Replace the eng cool LH fan. Refer to Engine Cooling Fan Replacement .

Did you complete the repair?

Go to Step 31

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2