Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: The auxiliary cooling fan is inoperative.

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 ignition, with the engine OFF.
3. With a scan tool, command the auxiliary cooling fan ON and OFF.

Does the auxiliary cooling fan turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

1. Disconnect the pusher fan relay.
2. Install a jumper wire between the battery positive voltage circuit and the auxiliary cooling fan motor supply voltage circuit on the switch side of the pusher fan relay.

Does the fan operate?

Go to Step 7

Go to Step 4

Did the fuse open when the jumper was installed?

Go to Step 5

Go to Step 6

Inspect the auxiliary cooling fan supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 15

1. With the jumper wire still in place, unplug the auxiliary cooling fan.
2. With a test lamp connected to a good ground probe the auxiliary cooling fan motor supply voltage circuit at the pusher relay.

Does the test lamp illuminate?

Go to Step 19

Go to Step 12

With a test lamp connected to a good ground probe the battery positive voltage circuits at the pusher relay.

Does the test lamp illuminate?

Go to Step 8

Go to Step 9

1. With a test lamp connected to battery positive, probe the auxiliary cooling fan relay control circuit at the pusher relay.
2. With a scan tool command the auxiliary cooling fan ON.

Does the test lamp illuminate?

Go to Step 13

Go to Step 10

Repair the battery positive voltage circuit of the auxiliary fan relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 19

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Inspect the control circuit of the auxiliary 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 19

Go to Step 17

Repair the auxiliary cooling fan motor supply voltage circuit for an open or high resistance. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 19

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Inspect the auxiliary cooling fan motor 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 15

Inspect for poor connections at the auxiliary fan relay. Refer to Circuit Testing and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 14

Replace the auxiliary fan relay.

Did you complete the replacement?

Go to Step 19

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Inspect for poor connections at the harness connector of the auxiliary cooling fan. Refer to Circuit Testing and Connector Repairs .

Did you find and correct the condition?

Go to Step 19

Go to Step 16

Replace the auxiliary cooling fan. Refer to Auxiliary Engine Coolant Fan and Fan Motor Replacement .

Did you complete the replacement?

Go to Step 19

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Inspect for poor connections at the engine control module (ECM). 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 ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 19

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2