Schematic Reference: Engine Cooling Schematics

Connector End View Reference: Cooling System Connector End Views

DEFINITION: One or both 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 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: A 3 second delay occurs before the powertrain control module (PCM) changes the cooling fan speed.

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

Go to Step 6

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

1. Disconnect the low speed fan relay.
2. Connect a jumper wire between the battery positive voltage circuit and the cooling fan motor supply voltage circuit of the low speed fan 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 right 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 right cooling fan electrical connector.
3. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the right 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 left cooling fan motor connector.
3. With a test lamp connected to a good ground, probe the cooling fan motor supply voltage circuit at the left 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 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 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 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 19

Inspect for poor connections at the low speed 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 20

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

Did you find and correct the condition?

Go to Step 25

Go to Step 21

Inspect for poor connections at the high speed 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 22

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 23

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 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 low speed fan 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 high speed fan relay.

Did you complete the replacement?

Go to Step 25

--

Replace the right cooling fan. Refer to Engine Cooling Fan Replacement .

Did you complete the replacement?

Go to Step 25

--

Replace the left cooling fan. Refer to Engine Cooling Fan 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