For 1990-2009 cars

Table 1: | Electric Cooling Fan Functional Check
Table 2: | Electric Cooling Fan Table #1
Table 3: | Electric Cooling Fan Table #2
Table 4: | Electric Cooling Fan Table #3

Refer to Engine Controls Schematics

#### Coolant Fans

Underhood Accessory Wiring Junction Block
Cell 14: G117
Cell 14: G117
Handling ESD Sensitive Parts Notice
Engine Controls Components
Powertrain Control Module Description
Vehicle Speed Sensor
A/C Compressor Controls
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views

### Circuit Description

Power for the fan motors is supplied through the Cool Fan 1 MaxiFuse® 30A and the Cool Fan 2 MaxiFuse® 30A in the

#### Underhood Accessory Wiring Junction Block Label

. The cooling fan relays are energized when current flows from the 2 Maxifuses® through the relay coils to ground through the powertrain control module (PCM). The Cool Fan 1 Relay Control Circuit is grounded for low speed fans operation. The Cool Fan 1 Relay Control Circuit and the Cool Fan 2 Relay Control Circuit are both grounded for high speed fans operation.

During low speed fans operation the PCM supplies a ground path for the Cool Fan 1 Relay. This closes the Cool Fan 1 Relay contacts, allowing current to flow from the

#### Underhood Accessory Wiring Junction Block Label

through the relay contacts to the Engine Coolant Fan Motor 1 RH. During low speed operation, the ground path for the Engine Coolant Fan Motor 1 RH is through the Coolant Fan 1 Relay and the Engine Coolant Fan Motor 2 LH. The result is a series circuit with both cooling fans running at low speed.

During high speed cooling fan operation the PCM supplies a ground path for the Cool Fan 1 Relay. The PCM also supplies a ground path for the Cool Fan Relay and the Cool Fan 2 Relay. This closes all 3 cooling fan relays. During high speed fans operation, both the Engine Coolant Fan Motor 1 RH and the Engine Coolant Fan Motor 2 LH are supplied current from the

#### Underhood Accessory Wiring Junction Block Label

and each cooling fan has its own ground path.

### Test Description

The numbers below refer to numbers on the diagnostic table:

1. The PCM will enable the engine cooling fans when certain Diagnostic Trouble Codes are set. Go to applicable DTC Table first before proceeding with this table.

2. Allow engine coolant temperature to cool below 100°C (212°F) before proceeding with diagnosis.

#### Electric Cooling Fan Functional Check

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain OBD System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Are any DTCs set? | -- | Go to applicable DTCs | Go to Step 3
3 |

1. Install a scan tool.
2. Engine coolant temperature must be below the specified value for all the fan diagnoses.
3. Turn on the Ignition, with the engine and A/C off.

Are the cooling fans off?

100°C (212°F)

Go to Step 4

Go to Cooling Fan table #1

4 | With a scan tool, command Low Speed Fans on. Are both cooling fans on? | -- | Go to Step 5 | Go to Cooling Fan table #2
5 | Important: : Allow a 3-5 second delay before determining if the fans have switched from low to high speed. With a scan tool, command High Speed Fans on. Do both cooling fans switch to high speed? | -- | Go to Step 6 | Go to Cooling Fan table #3
6 |

1. Exit outputs screen on the scan tool.
2. Idle the engine leaving the A/C off.

Are the cooling fans on?

--

Go to Step 8

Go to Step 7

7 | Turn on the A/C. Are the cooling fans on? | -- | System OK | Go to Step 9
8 | Does the scan tool display A/C request as YES? | -- | Go to Cooling Insufficient - Air Conditioning (A/C) System in Heating, Ventilation, and Air Conditioning | Go to Step 10
9 | Does the scan tool display A/C request as YES? | -- | Go to Powertrain Control Module Controlled Air Conditioning (A/C) Circuit Diagnosis | Go to Cooling Insufficient - Air Conditioning (A/C) System in Heating, Ventilation, and Air Conditioning
10 | Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | System OK | --

#### Electric Cooling Fan Table #1

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Step 2 | Go to Cooling Fan Functional Check
2 | Disconnect Cool Fan 1 Relay. Are both fans off? | -- | Go to Step 8 | Go to Step 3
3 | Disconnect Cool Fan Relay. Are both fans off? | -- | Go to Step 4 | Go to Step 10
4 |

1. Disconnect the left fan.
2. Probe terminal B of the left fan connector using a test lamp that is connected to a known good ground.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 5

5 | Probe terminal A of the left fan connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 6
6 | Probe the High Speed Fans control circuit (473) at the Cool Fan Relay connector in the

#### Underhood Accessory Wiring Junction Block Label

using a test lamp that is connected to battery positive voltage.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 13

7 |

1. Turn off the ignition.
2. Leave the test lamp installed.
3. Disconnect the PCM.
4. Turn on the ignition, with the engine off.

Is the test lamp still illuminated?

--

Go to Step 14

Go to Step 16

8 | Probe the Low Speed Fans Control circuit (335) at the Cool Fan 1 Relay connector using the test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 13
9 |

1. Turn off the ignition.
2. Leave the test lamp installed.
3. Disconnect the PCM.
4. Turn on the ignition, with the engine off.

Is the test lamp still illuminated?

--

Go to Step 14

Go to Step 16

10 | Repair the RH fan feed circuit (409) for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | Go to Step 15
11 | Repair the LH fan feed circuit (532) for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
12 | Repair the short to voltage in the Cool Fan Relay feed circuit (504). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
13 | Replace the Cool Fan 1 Relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
14 | Repair the High Speed Fans Control circuit (473) or the Low Speed Fans Control circuit (335) for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
15 | Replace the Cool Fan Relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
16 | Important:: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --

#### Electric Cooling Fan Table #2

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Step 2 | Go to Cooling Fan Functional Check
2 | Did either fan turn on when Cool Fan 1 Relay was commanded on? | -- | Go to Step 3 | Go to Step 5
3 |

1. Install a scan tool.
2. With a scan tool, command High Speed Fans on.

Did the other fan turn off?

--

Go to Step 19

Go to Step 4

4 | With the Low Speed Fans Commanded ON, Disconnect Cool Fan Relay. Did the left fan turn off? | -- | Go to Step 20 | Go to Step 21
5 |

1. Disconnect Cool Fan 1 Relay.
2. Probe Low Speed Fans Control circuit (335) at the Cool Fan 1 Relay Connector using a test lamp that is connected to battery positive voltage.
3. With a scan tool, command Low Speed Fans on.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 13

6 | Probe both feed circuits (342) at the Cool Fan 1 Relay Connector using a test lamp that is connected to ground. Does test lamp illuminate for both circuits? | -- | Go to Step 7 | Go to Step 22
7 | Important: : Leave jumper in place for remainder of this table. Connect a fused jumper wire between the switch feed circuit (342) and the LH fan feed circuit (532) at the Cool Fan 1 Relay Connector. Do both fans turn on? | -- | Go to Step 23 | Go to Step 8
8 |

1. Disconnect the left fan.
2. Probe fan harness connector terminal B with a test lamp that is connected to a known good ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 24

9 | Connect a second fused jumper wire between the left fan harness connector terminals. Is the right fan on? | -- | Go to Step 16 | Go to Step 10
10 |

1. Reconnect the left fan.
2. Disconnect Cool Fan Relay.
3. Probe the switch feed circuit (504) at Cool Fan Relay connector using a test lamp that is connected to a known good ground.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 25

11 | Using a second jumper wire, jumper the switch feed circuit (504) and the RH fan feed circuit (409) together at Cool Fan Relay connector. Do the fans come on? | -- | Go to Step 26 | Go to Step 12
12 |

1. Reconnect Cool Fan Relay.
2. Disconnect the right fan.
3. Probe right fan harness connector terminal B with a test lamp that is connected to a known good ground.

Is the left fan on?

--

Go to Step 16

Go to Step 18

13 |

1. Keep the test lamp connected.
2. Turn off the ignition.
3. Disconnect the PCM.
4. Probe the Low Speed Fans Control circuit at the PCM connector, with a fused jumper wire that is connected to a known good ground.

Did the test lamp illuminate?

--

Go to Step 20

Go to Step 21

14 | Inspect the PCM connections. Repair faulty connections as necessary. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | Go to Step 27
15 | Repair the Low Speed Fans Control circuit (335) for an open or shorted to battery positive voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
16 | Inspect the fan motor ground circuit for a open or the fan motor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs or Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | Go to Step 17
17 | Replace the faulty fan motor. Refer to Engine Coolant Fan Motor Replacement in Engine Cooling. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
18 | Repair the RH fan feed circuit (409) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
19 | Replace the fan which was not operating. Refer to Engine Coolant Fan Motor Replacement in Engine Cooling. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
20 | Replace Cool Fan Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
21 | Repair the Cool Fan Relay feed circuit (504) for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | Go to Step 26
22 | Repair the open or the grounded circuit for the circuit that did not light. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
23 | Replace Cool Fan 1 Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
24 | Repair the LH fan feed circuit (532) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
25 | Repair the Cool Fan Relay switch feed circuit (504) for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
26 | Replace Cool Fan Relay . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
27 | Important: : Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --

#### Electric Cooling Fan Table #3

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Step 2 | Go to Cooling Fan Functional Check
2 |

1. With a scan tool, command Low Speed Fans on.
2. Command High Speed Fans on.

Did both fans operate with no change?

--

Go to Step 8

Go to Step 3

3 | Did the left fan stop operating? | -- | Go to Step 9 | Go to Step 4
4 |

1. Disconnect Cool Fan 2 Relay.
2. Probe the High Speed Fans Control circuit (473) at Cool Fan 2 Relay connector using a test lamp that is connected to battery positive voltage.
3. Command High Speed Fans on using a scan tool.

Does the test lamp illuminate after several seconds?

--

Go to Step 5

Go to Step 12

5 | Probe the coil feed circuit (1442) at Cool Fan 2 Relay connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 13
6 | Probe the switch feed circuit (1442) at the Cool Fan 2 Relay connector using a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 14
7 | Jumper the switch feed circuit (1442) and the RH fan feed circuit (409) together at the Cool Fan 2 Relay connector. Is the right fan on? | -- | Go to Step 15 | Go to Step 16
8 |

1. Turn off the ignition.
2. Disconnect the PCM.
3. Disconnect Cool Fan 1 Relay.
4. Jumper the switch feed circuit (342) and the RH fan feed circuit (532) together at the Cool Fan 1 Relay connector.
5. Turn the ignition on.
6. Probe the PCM harness connector for the High Speed Fans Control circuit with a fused jumper that is connected to a known good ground.

Do the fans switch from low to high speed?

--

Go to Step 22

Go to Step 17

9 |

1. Disconnect Cool Fan Relay.
2. Probe the High Speed Fans Control Cirucit (473) at the Cool Fan Relay connector using a test lamp that is connected to battery positive voltage.
3. Command High Speed Fans on using a scan tool.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 18

10 | Probe the ground circuit (1050) at the Cool Fan Relay connector using a test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 19
11 | Probe the coil feed circuit (1442) at the Cool Fan Relay connector using a test lamp that is connected to a known good ground. Does the test lamp illuminate? | -- | Go to Step 20 | Go to Step 21
12 | Repair the High Speed Fans Control circuit (473) for an open between Cool Fan Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
13 | Repair the open in the Cool Fan 2 Relay coil feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
14 | Repair the open in the Cool Fan 2 Relay switch feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
15 | Replace Cool Fan 2 Relay. Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --
16 | Repair the open in the RH fan feed circuit (409) between Cool Fan 3 Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
17 | Repair the High Speed Fans Control circuit (473) for an open or for a short to battery positive voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
18 | Repair the open in the High Speed Fans Control circuit (473) between Cool Fan Relay and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
19 | Repair the open in the ground circuit (1050). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
20 | Replace the Cool Fan relay. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
21 | Repair the open in Cool Fan Relay coil feed circuit (1442). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Cooling Fan Functional Check | --
22 | Inspect the PCM connections. Refer to Testing for Intermittent Conditions and Poor Connections , and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Cooling Fan Functional Check | Go to Step 23
23 | Important: : Program the replacement PCM. Replace the PCM.Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Cooling Fan Functional Check | --