Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference : Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views DEFINITION: One or both cooling fan motors are inoperative in either high, low, or both speeds. | |||
1 | Did you perform the Diagnostic System Check - Engine Cooling? | Go to Step 2 | |
2 |
Do the low speed engine cooling fans turn ON and OFF with each command? | Go to Step 3 | Go to Step 4 |
3 |
Important:: A 3 second delay occurs before the powertrain control module (PCM)/engine control module (ECM) 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 in Wiring Systems | Go to Step 11 |
4 |
Important: Do NOT remove the 20 A fused jumper wire connected during this step. Use a second 20 A fused jumper wire while performing the following steps. Do both cooling fans operate in low speed? | Go to Step 13 | Go to Step 5 |
5 |
Do both cooling fans operate in low speed? | Go to Step 14 | Go to Step 6 |
6 | Reconnect the second 20-A fused jumper between the battery positive voltage circuit of the cooling fan 2 relay and the cooling fan motor supply voltage circuit of the cooling fan 2 relay. Does the right cooling fan operate in high speed? | Go to Step 9 | Go to Step 7 |
7 |
Does the left cooling fan operate in high speed? | Go to Step 16 | Go to Step 8 |
8 | Reconnect 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 |
9 |
Does the right cooling fan operate in high speed? | Go to Step 17 | Go to Step 10 |
10 | Reconnect 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 |
11 | Does the right cooling fan operate in high speed? | Go to Step 12 | Go to Step 15 |
12 |
Does the left cooling fan operate properly in high speed? | Go to Step 14 | Go to Step 19 |
13 | 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 28 | Go to Step 23 |
14 | 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 28 | Go to Step 24 |
15 | Inspect for poor connections at the cooling fan 3 or 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 28 | Go to Step 25 |
16 | 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 |
17 | 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 |
18 | Repair the left cooling fan motor supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 28 | -- |
19 | Repair the left cooling fan motor ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 28 | -- |
20 | Repair the right cooling fan motor ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 28 | -- |
21 | 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 | -- |
22 | Repair the left cooling fan low reference circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 28 | -- |
23 | Replace the cooling fan 1 relay. Did you complete the replacement? | Go to Step 28 | -- |
24 | Replace the cooling fan 2 relay. Did you complete the replacement? | Go to Step 28 | -- |
25 | Replace the cooling fan 3 or S/P relay. Did you complete the replacement? | Go to Step 28 | -- |
26 | Replace the right cooling fan. Refer to Engine Coolant Fan Motor Replacement . Did you complete the replacement? | Go to Step 28 | -- |
27 | Replace the left cooling fan. Refer to Engine Coolant Fan Motor Replacement . Did you complete the replacement? | Go to Step 28 | -- |
28 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
