Did you perform the Engine Cooling Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Cooling

1. Turn OFF the ignition.
2. Connect a 10 amp fused jumper wire between pin 1 and pin 6 of the coolant fan test connector.

Does all three cooling fans operate?

Go to Step 3

Go to Cooling Fan Inoperative

Important: The primary cooling fan temperature switch will effect the cooling fans and auxiliary coolant pump operation if the sensor fails. This table assumes the sensor is good due to the cooling fan symptoms that would result.

Turn OFF the ignition.

Does the auxiliary water pump operate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 4

1. Remove the K26 fan control relay.
2. With a test lamp connected to a good ground, probe circuit A223 at the K26 relay connector.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

Connect a 20 amp fused jumper wire between circuit A223 and circuit AP1 of the K26 relay connector.

Does the pump operate?

Go to Step 14

Go to Step 6

1. Remove the jumper at K26 relay.

Install the K26 relay.

Remove the K22 auxiliary water pump relay.

2. With a test lamp connected to a good ground, probe circuit AP3 of the K22 relay connector.

Does the test lamp illuminate?

Go to Step 7

Go to Step 12

Connect a 20 amp fused jumper wire between circuit AP3 and circuit XU2 of the K22 relay connector.

Does the pump operate?

Go to Step 16

Go to Step 8

1. Remove the jumper at K22 relay.

Install the K22 relay.

Disconnect the auxiliary water pump connector.

2. With a test lamp connected to a good ground, probe circuit XU2 of the auxiliary water pump connector.

Does the test lamp illuminate?

Go to Step 9

Go to Step 13

Connect a test lamp between circuit XU2 and circuit F6 of the auxiliary water pump connector.

Does the test lamp illuminate?

Go to Step 18

Go to Step 10

Repair circuit F6 of the auxiliary water pump for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

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Repair circuit A223 of the K26 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

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Repair circuit AP1 or AP3 of the K22 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

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Repair circuit XU2 of the auxiliary water pump for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

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Inspect for poor connections at the K26 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find the problem?

Go to Step 20

Go to Step 15

Replace the K26 fan control relay.

Did you complete the repair?

Go to Step 20

Inspect for poor connections at the K22 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find the problem?

Go to Step 20

Go to Step 17

Replace the K22 auxiliary water pump relay.

Did you complete the repair?

Go to Step 20

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Inspect for poor connections at the harness connector of the water auxiliary pump. 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 20

Go to Step 19

Replace the water auxiliary pump. Refer to Auxiliary Water Pump Replacement

Did you complete the repair?

Go to Step 20

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2