Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Cooling Schematics Connector End View Reference: Cooling System Connector End Views DEFINITION: One or both engine cooling fan motors do not operate properly in high or low speed modes. | |||
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 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 in Wiring Systems | Go to Step 12 |
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 22 | Go to Step 5 |
5 |
Do both cooling fans operate in low speed? | Go to Step 23 | Go to Step 6 |
6 | Connect the second 20-A fused jumper between the battery positive voltage circuit and the cooling fan motor supply voltage circuit of the 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 25 | Go to Step 8 |
8 | 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 29 | Go to Step 30 |
9 |
Does the right cooling fan operate in high speed? | Go to Step 26 | Go to Step 10 |
10 | Connect the second 20-Amp fused jumper wire from the coil side battery positive voltage circuit to the 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 11 | Go to Step 31 |
11 | Probe the battery positive voltage circuit on the switch side of the fan 1 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 27 | Go to Step 32 |
12 | Is the right cooling fan operating properly in high speed? | Go to Step 19 | Go to Step 13 |
13 |
Does the test lamp turn ON and OFF with each command? | Go to Step 15 | Go to Step 14 |
14 | Probe the battery positive voltage circuit on the coil side of the fan 3 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 34 | Go to Step 33 |
15 | Install a 20 amp fused jumper between the battery positive voltage circuit on the switch side of the fan 3 relay and the cooling fan motor supply voltage circuit. Does the right cooling fan operate in high speed? | Go to Step 24 | Go to Step 16 |
16 | Probe the battery positive voltage circuit on the switch side of the fan 3 relay with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 17 | Go to Step 33 |
17 |
Does the test lamp illuminate? | Go to Step 25 | Go to Step 18 |
18 | Probe the cooling fan motor supply voltage circuit of the right cooling fan electrical connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 29 | Go to Step 30 |
19 |
Does the left cooling fan operate in high speed? | Go to Step 20 | Go to Step 28 |
20 |
Does the test lamp turn ON and OFF with each command? | Go to Step 23 | Go to Step 21 |
21 | Probe the battery positive voltage circuit of the fan 2 relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 34 | Go to Step 33 |
22 | Inspect for poor connections at the 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 40 | Go to Step 35 |
23 | Inspect for poor connections at the 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 40 | Go to Step 36 |
24 | Inspect for poor connections at the fan 3 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 40 | Go to Step 37 |
25 | 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 40 | Go to Step 38 |
26 | 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 40 | Go to Step 39 |
27 | Repair the left cooling fan motor supply voltage circuit for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 40 | -- |
28 | Repair the left cooling fan ground circuit for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 40 | -- |
29 | Repair the right cooling fan ground circuit for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 40 | -- |
30 | Repair the right cooling fan motor supply voltage circuit for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 40 | -- |
31 | Repair the left cooling fan low reference circuit for a short to ground or an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 40 | -- |
32 | Repair the fan 1 relay battery positive voltage circuit for an open. Is the repair complete? | Go to Step 40 | -- |
33 | Repair the battery positive voltage circuit for the fan 2 relay and fan 3 relay for an open. Is the repair complete? | Go to Step 40 | -- |
34 | Repair the high speed cooling fan relay control circuit for an open. Is the repair complete? | Go to Step 40 | -- |
35 | Replace the fan 1 relay. Is the repair complete? | Go to Step 40 | -- |
36 | Replace the fan 2 relay. Is the repair complete? | Go to Step 40 | -- |
37 | Replace the fan 3 relay. Is the repair complete? | Go to Step 40 | -- |
38 | Replace the right cooling fan. Refer to Engine Coolant Fan Motor Replacement . Is the repair complete? | Go to Step 40 | -- |
39 | Replace the left cooling fan. Refer to Engine Coolant Fan Motor Replacement . Is the repair complete? | Go to Step 40 | -- |
40 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
