For 1990-2009 cars

## Cooling Fan Inoperative - Auxiliary All Fans Inoperative

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Cooling Fan Schematics DEFINITION: The cooling fan and both auxiliary coolant fans are inoperative.
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | Go to Cooling Fan System Check
2 |

1. Start the engine.
2. With a scan tool observe the engine coolant temperature.

Does the low speed fans turn on approximately 100°C (212°F)?

Go to Intermittents and Poor Connections Diagnosis

Go to Step 3

3 |

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

Does the low speed fans turn ON?

Go to Step 7

Go to Step 4

4 |

1. Remove the K26 fan control relay.
2. With a test lamp connected to a good ground, probe circuit A6 of the K26 relay.

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

5 | Install a test lamp between circuit A6 and circuit XP3 of the K26 relay. Does the test lamp illuminate? | Go to Step 6 | Go to Step 13
6 | With a test lamp connected to a good ground, probe circuit A222 of the K26 relay. Does the test lamp illuminate. | Go to Step 18 | Go to Step 8
7 |

1. Remove the jumper wire at the cooling fan test connector.
2. Disconnect the Primary cooling fan temperature switch.
3. Install a 20 amp fused jumper between circuit XP30 and circuit F600 of the Primary cooling fan temperature switch.

Does the cooling fans turn ON.

Go to Step 24

Go to Step 12

8 | Inspect circuit A221, A222, or A223 for a short to ground. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 9
9 |

1. Verify that voltage is supplied to circuit A222.
2. Disconnect auxiliary cooling fan 1.
3. Install a test lamp between circuit A222 and circuit AM1 at the K26 relay.

Does the test lamp illuminate?

Go to Step 15

Go to Step 10

10 | Inspect the auxiliary coolant fan 1 for a short to ground. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 11
11 |

1. Connect the auxiliary coolant fan 1.
2. Disconnect the auxiliary water pump.
3. Install a test lamp between circuit A223 and circuit AP1 of the K26 relay.

Does the test lamp illuminate?

Go to Step 16

Go to Step 22

12 | Inspect circuit XP30 of the primary cooling fan temperature switch for an open or high resistance. Intermittents and Poor Connections Diagnosis and Testing for Continuity in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 17
13 | Repair circuit XP3 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 26 | --
14 | Repair circuit A6 of the K26 relay for an open, high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | --
15 | Repair circuit A1, AM12 or AM13 of the K26 relay for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | --
16 | Repair circuit AP1, AP2, AP3, or XU2 of the K26 relay for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | --
17 | Repair circuit F600 of the primary cooling fan temperature switch for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 26 | --
18 | Inspect for poor connections at the K26 relay. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 26 | Go to Step 19
19 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K26.

Did you complete the repair?

Go to Step 26

--

20 | Inspect for poor connections at the auxiliary coolant fan 1. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 26 | Go to Step 21
21 | Replace the auxiliary coolant fan 1. Refer to Auxiliary Engine Coolant Fan and Fan Motor Replacement . Did you complete the repair? | Go to Step 26 | --
22 | Inspect for poor connections at the auxiliary water pump. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 26 | Go to Step 23
23 | Replace the auxiliary water pump. Refer to Auxiliary Water Pump Replacement . Did you complete the repair? | Go to Step 26 | --
24 | Inspect for poor connections at the primary cooling fan temperature switch. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 26 | Go to Step 25
25 | Replace the primary cooling fan temperature switch . Refer to Engine Cooling Fan Control Switch Replacement . Did you complete the repair? | Go to Step 26 | --
26 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2

## Cooling Fan Inoperative - Auxiliary Auxiliary Fan 1 and or 2 Inoperative

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Cooling Fan Schematics DEFINITION: The auxiliary coolant fan 1 and or 2 are inoperative on low speed, high speed or both.
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | Go to Cooling Fan System Check
2 |

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

Are both auxiliary coolant fans inoperative?

Go to Step 18

Go to Step 3

3 | With the jumper wire still installed between pin 1 and pin 6 . Is the auxiliary coolant fan 2 inoperative? | Go to Step 15 | Go to Step 4
4 |

1. Remove the fused jumper wire at the coolant fan test connector.
2. Install a scan tool.
3. Start the engine.
4. With a scan tool, observe the engine coolant temperature parameter.

Does the auxiliary coolant fan 1 and auxiliary coolant fan 2 operate in high speed above 105°C (221°F)?

Go to Intermittents and Poor Connections Diagnosis

Go to Step 5

5 | With the vehicle still running above 105°C (221°F). Are both fans operating at low speed. | Go to Step 13 | Go to Step 6
6 |

1. Turn OFF the ignition.
2. Ground pin 1 at the coolant fan test connector.
3. Also ground pin 4 at the coolant fan test connector.
4. Turn ON the ignition.

Is the auxiliary coolant fan 1 inoperative?

Go to Step 7

Go to Step 9

7 |

1. Turn OFF the ignition.
2. With pin 1 and pin 4 still grounded.
3. Remove the fan control relay K52.
4. Turn ON the ignition.
5. With a test lamp connected to a good ground, probe circuit X30 at the K52 relay.

Does the test lamp illuminate?

Go to Step 8

Go to Step 28

8 | Install a test lamp between circuit XM123 and circuit X30 of the K52 relay. Does the test lamp illuminate? | Go to Step 45 | Go to Step 29
9 |

1. Turn OFF the ignition.
2. With pin 1 and pin 4 still grounded.
3. Remove the fan control relay K28.
4. Turn ON the ignition.
5. With a test lamp connected to a good ground, probe circuit X400 at the K28 relay.

Does the test lamp illuminate?

Go to Step 10

Go to Step 30

10 | Install a test lamp between circuit X400 and XM124 of the K28 relay. Does the test lamp illuminate? | Go to Step 11 | Go to Step 31
11 | With a test lamp connected to a good ground, probe circuit A14 at the K28 relay. Does the test lamp illuminate? | Go to Step 12 | Go to Step 32
12 | Connect a test lamp between circuit A14 and circuit AM4. Does the test lamp illuminate. | Go to Step 43 | Go to Step 33
13 |

1. Turn OFF the ignition.
2. Install a 10 amp fused jumper wire between pin 1 and pin 6 of the cooling fan test connector.
3. Disconnect the secondary cooling fan temperature switch.
4. Install a 10 amp fused jumper wire between circuit XM122 and circuit F60 of the secondary cooling fan temperature switch.
5. Turn ON the ignition.

Does the auxiliary coolant fan 1 and coolant fan 2 operate at high speed?

Go to Step 39

Go to Step 14

14 | Inspect circuit XM122 of the secondary cooling fan temperature switch for an open or high resistance. Refer to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 49 | Go to Step 34
15 | Disconnect the auxiliary coolant fan 2. Does the auxiliary coolant fan 1 turn OFF? | Go to Step 25 | Go to Step 16
16 | Remove the fan control relay K52. Does the auxiliary coolant fan 1 turn OFF? | Go to Step 17 | Go to Step 35
17 | Inspect circuit AM3, AM4 and AM5 of the K52 relay for a short to ground. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition? | Go to Step 49 | Go to Step 45
18 |

1. Remove the K52 relay.
2. Install a 10 amp fused jumper wire between circuit XU3 and circuit AM3 of the of the K52 relay.

Does the auxiliary coolant fan 1 and coolant fan 2 turn ON?

Go to Step 45

Go to Step 19

19 |

1. Remove the fused jumper wire at the K52 relay.
2. Install the K52 relay.
3. With a test lamp connected to a good ground, probe circuit A222 of the K26 relay.

Does the test lamp illuminate?

Go to Step 20

Go to Step 36

20 | Install a 30 amp fused jumper wire between circuit A222 and circuit AM1 of the K26 relay. Does the auxiliary coolant fan 1 and coolant fan 2 turn ON? | Go to Step 47 | Go to Step 21
21 |

1. Remove the fused jumper wire at the K26 relay.
2. Install the K26 relay.
3. With a test lamp connected to a good ground, probe circuit AM13 of the coolant fan 1 connector.

Does the test lamp illuminate?

Go to Step 22

Go to Step 37

22 | Install a 30 amp fused jumper wire between circuit AM13 and circuit XU3 of the cooling fan 1 connector. Does the auxiliary coolant fan 2 operate at high speed? | Go to Step 41 | Go to Step 23
23 |

1. Disconnect the auxiliary coolant fan 2.
2. With a test lamp connected to a good ground, probe circuit AM5 of the auxiliary coolant fan 2 connector.

Does the test lamp illuminate?

Go to Step 24

Go to Step 27

24 | Inspect circuit F4 of the auxiliary coolant fan 2 for an open. Did you find and correct the condition? | Go to Step 49 | Go to Step 25
25 | Inspect for poor connections at the auxiliary coolant fan 2. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 26
26 | Replace the auxiliary coolant fan 2. Refer to Auxiliary Engine Coolant Fan and Fan Motor Replacement . Did you complete the repair? | Go to Step 49 | --
27 | Inspect circuit AM5 and circuit AM3 of the auxiliary coolant fan 2 for an open or high resistance. Did you find and correct the condition? | Go to Step 49 | Go to Step 38
28 | Repair circuit X30, X68, X67 or X868 of the K52 relay for an open or high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
29 | Repair circuit XM123 of the K52 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
30 | Repair circuit X400 of the K28 relay for an open, high resistance or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
31 | Repair circuit XM124 of the K28 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
32 | Repair circuit A14 of the K28 relay for an open or high resistance or a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
33 | Repair circuit AM4 of the K28 relay for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
34 | Repair circuit F60 of the secondary cooling fan temperature switch for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
35 | Repair circuit XU3 of the K52 reley for a shart to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
36 | Repair circuit A222 of the K26 reley for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
37 | Repair circuit AM13 or AM1 of the auxiliary coolant fan 1 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
38 | Repair circuit XU3 of the auxiliary coolant fan 1 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 49 | --
39 | Inspect for poor connections at the secondary cooling fan temperature switch. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 40
40 | Replace the secondary cooling fan temperature switch . Refer to Engine Cooling Fan Control Switch Replacement . Did you complete the repair? | Go to Step 49 | --
41 | Inspect for poor connections at the auxiliary coolant fan 1. Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 42
42 | Replace the auxiliary coolant fan 1. Refer to Auxiliary Engine Coolant Fan and Fan Motor Replacement . Did you complete the repair? | Go to Step 49 | --
43 | Inspect for poor connections at the K28 relay. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 44
44 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K28.

Did you complete the repair?

Go to Step 49

--

45 | Inspect for poor connections at the K52 relay. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 46
46 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K52.

Did you complete the repair?

Go to Step 49

--

47 | Inspect for poor connections at the K26 relay. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find the problem? | Go to Step 49 | Go to Step 48
48 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K26.

Did you complete the repair?

Go to Step 49

--

49 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2

## Cooling Fan Inoperative - Auxiliary A/C Cooling Low Speed

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | Go to Cooling Fan System Check
2 |

1. Turn OFF the ignition.
2. Connect a 5 A fused jumper between pin 1 and pin 6 of the cooling fan test connector.

Does the auxiliary engine coolant fan #1 and auxiliary engine coolant fan #2 operate at low speed?

Go to Step 3

Go to Cooling Fan Inoperative - Auxiliary

3 |

1. Remove the fused jumper.
2. Turn ON the ignition, with the engine OFF.

Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

3. Remove fan control relay K87.
4. Test circuit A221 of the fan control relay K87 connector for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 4

4 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Test circuit F2l of the fan control relay K87 connector for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5 |

1. Start the engine.
2. Turn the A/C compressor ON

Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

3. With a test lamp connected to a good ground, probe circuit U4 of the K87 relay.

Does the test lamp illuminate?

Go to Step 8

Go to Step 6

6 | Test circuit U4 of the K87 relay for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 7
7 | Refer to HVAC Compressor Controls System Check in HVAC Systems-Automatic. Did you complete the repair? | Go to Step 11 | --
8 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Test circuit AM12 of the fan control relay K87 connector for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

9 | Inspect for poor connections at the harness connector of the fan control relay K87. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 10
10 | Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K87.

Did you complete the repair?

Go to Step 11

--

11 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2

## Cooling Fan Inoperative - Auxiliary A/C Cooling High Speed

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Engine Cooling Diagnostic System Check? | Go to Step 2 | Go to Cooling Fan System Check
2 |

1. Start the engine.
2. Turn the A/C compressor ON.
3. Connect a 5 amp fused jumper between pin 6 and 2 of the cooling fan test connector.

Does the Auxiliary fan #1 and Auxiliary fan #2 operate at high speed?

Go to Step 4

Go to Step 3

3 | Inspect circuit XM10 of the K28 fan control relay for an open. Notice: Installation of the proper relay is critical. If an enhanced relay -- equipped with a diode -- is installed into a position requiring a standard relay -- equipped without a diode -- excessive current will damage any components associated with the relay or its associated circuits.

Replace the fan control relay K28 if these circuits are OK.

Did you complete the repair?

Go to Step 5

--

4 |

1. Inspect circuit XM120 and circuit F57 of the A/C compressor refigerant pressure switch for an open.
2. Replace the A/C compressor refrigerant pressure switch if these circuit are OK.

Did you complete the repair?

Go to Step 5

--

5 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2