Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Cooling Schematics DEFINITION: One or both engine cooling fan motors do not operate properly in high or low speed. | |||
1 | Did you perform the Engine Cooling Diagnostic System Check? | 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 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 in Wiring Systems | Go to Step 13 |
4 | Test the battery positive voltage circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 5 |
5 | Test the cooling fan motor supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 6 |
6 |
Important: Following this step, do not remove the 20 A fused jumper wire that is connected during this step. While performing the following steps, use a second 20 A fused jumper wire. Do both cooling fans operate in low speed? | Go to Step 15 | Go to Step 7 |
7 |
Do both cooling fans operate in low speed? | Go to Step 16 | Go to Step 8 |
8 | Connect the second 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 right cooling fan operate in high speed? | Go to Step 11 | Go to Step 9 |
9 |
Does the left cooling fan operate in high speed? | Go to Step 23 | Go to Step 10 |
10 | Connect 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 27 | Go to Step 28 |
11 |
Does the right cooling fan operate in high speed? | Go to Step 24 | Go to Step 12 |
12 | Connect 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 25 | Go to Step 29 |
13 | Is the right cooling fan operating properly in high speed? | Go to Step 14 | Go to Step 19 |
14 |
Does the left cooling fan operate properly in high speed? | Go to Step 16 | Go to Step 26 |
15 | 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 35 | Go to Step 30 |
16 | Test the battery positive voltage circuit of the cooling fan s/p relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 17 |
17 | Test the high speed cooling fan relay control circuit of the cooling fan s/p relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 18 |
18 | 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 35 | Go to Step 31 |
19 | Test the battery positive voltage circuit of the cooling fan 2 relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 20 |
20 | Test the high speed cooling fan relay control circuit of the cooling fan 2 relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 21 |
21 | Test the cooling fan motor supply voltage circuit of the right cooling fan for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 35 | Go to Step 22 |
22 | 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 35 | Go to Step 32 |
23 | 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 35 | Go to Step 33 |
24 | 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 35 | Go to Step 34 |
25 | Repair the left cooling fan supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 35 | -- |
26 | Repair the left cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 35 | -- |
27 | Repair the right cooling fan ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 35 | -- |
28 | Repair the right cooling fan supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 35 | -- |
29 | Repair the left cooling fan low reference circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 35 | -- |
30 | Replace the cooling fan 1 relay. Did you complete the repair? Is the repair complete? | Go to Step 35 | -- |
31 | Replace the cooling fan s/p relay. Did you complete the repair? Is the repair complete? | Go to Step 35 | -- |
32 | Replace the cooling fan 2 relay. Did you complete the repair? Is the repair complete? | Go to Step 35 | -- |
33 | Replace the right cooling fan. Refer to Engine Cooling Fan Replacement . Did you complete the repair? Is the repair complete? | Go to Step 35 | -- |
34 | Replace the left cooling fan. Refer to Engine Cooling Fan Replacement . Did you complete the repair? Is the repair complete? | Go to Step 35 | -- |
35 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
