For 1990-2009 cars

## Cooling Fan Inoperative Main

Table 1: | Reference Table

#### Reference Table

Problem | Causes
--- | ---
Both fans inoperative |

• | Open in the supply voltage circuit to the fan 1 and the engine main relays in fuse and relay block 1

• | High resistance or poor connection in fuse and relay block 1

• | Faulty engine main relay

• | Short to ground in the fan 1 or the fan 2 coil ground circuit

• | Engine coolant temperature (ECT) sensor or powertrain control module (PCM) malfunction

Main fan inoperative |

• | Faulty main fan motor

• | Faulty fan 1 relay

• | Open in the main fan circuit

Auxiliary fan inoperative |

• | Faulty auxiliary fan motor

• | Faulty fan 2 relay

• | Open in the auxiliary fan circuit

Both fans inoperative in low speed |

• | Faulty fan 2 relay

• | Faulty fan 3 relay

• | Open in the series portion of fan circuit

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Cooling Schematics .
The main fan motor is mounted on the left side of the radiator/condenser assembly. The fans run at low speed in series configuration when the A/C is operating and the engine coolant temperature (ECT) is below 83°C (181°F). The fans run at high speed in parallel configuration when the ECT is above 93°C (199°F).

A short to ground in the coil ground circuit of the fan 1 and 2 relays will cause both fans to be inoperative once the ECT reaches 93°C (199°F). This table assumes that the auxiliary fan motor is functioning normally.

1 | Did you review the Cooling System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Cooling
2 | Run the engine until operating temperature is reached and the thermostat opens. Do the cooling fans operate? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3
3 | Exchange the fan 1 relay with a known good relay (the fan 3 relay, the A/C MG relay, or the horn relay). Refer to Cooling Fan Relay Replacement . Did you find and correct the condition? | Go to Step 14 | Go to Step 4
4 |

1. Stop the engine.
2. Disconnect the main fan motor connector.
3. Connect a test lamp across the main fan motor connector.
4. Start the engine.

Does the test lamp illuminate?

Go to Step 12

Go to Step 5

5 | Test the main fan motor ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 6
6 | Test the main fan motor supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 7
7 | Test the supply voltage circuit to fuse and relay block 1 for an open. This circuit supplies voltage to the coils of the fan 1 relay and the engine main relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 8
8 | Test the fan 1 relay switch supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 9
9 | Test the engine main relay switch supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10
10 | Test the engine main relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 11
11 |

1. Remove fuse and relay block 1 from the inner fender.
2. Inspect the connectors in fuse and relay block 1 for poor connections and high resistance. 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 14

--

12 | Inspect for a poor connection at the harness connector of the main fan motor. 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 14 | Go to Step 13
13 | Replace the main fan motor. Refer to Engine Cooling Fan Replacement . Did you complete the replacement? | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3

## Cooling Fan Inoperative Auxiliary

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Cooling Schematics
The auxiliary fan motor is mounted on the right side of the radiator/condenser assembly. The fans run at low speed in series configuration when the A/C is operating and the engine coolant temperature (ECT) is below 83°C (181°F). The fans run at high speed in parallel configuration when the ECT is above 93°C (199°F).

A short to ground in the ground circuit of the fan 1 and 2 relays will cause both fans to be inoperative once the ECT reaches 93°C (199°F). This table assumes that the main fan motor is functioning normally.

1 | Did you review the Cooling System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Cooling
2 | Run the engine until operating temperature is reached and the thermostat opens. Do the cooling fans operate? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3
3 |

1. Stop the engine.
2. Disconnect the auxiliary fan motor connector.
3. Connect a test lamp across the auxiliary fan motor connector.
4. Start the engine.

Does the test lamp illuminate?

Go to Step 7

Go to Step 4

4 | Test auxiliary fan motor supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 5
5 |

1. Remove the fan 2 relay from fuse and relay block 2.
2. Test the circuit between the auxiliary fan motor and the fan 2 relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
3. Test the fan 2 relay ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6 | Replace the fan 2 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 9 | --
7 | Inspect for a poor connection at the harness connector of the auxiliary fan motor. 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 9 | Go to Step 8
8 | Replace the auxiliary fan motor. Refer to Engine Cooling Fan Replacement . Did you complete the replacement? | Go to Step 9 | --
9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3

## Cooling Fan Inoperative Inop in Low Speed

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Cooling Schematics
The main fan motor is mounted on the left side of the radiator/condenser assembly. The auxiliary fan motor is mounted on the right side of the radiator/condenser assembly. The fans run at low speed in series configuration when the A/C is operating and the engine coolant temperature (ECT) is below 83°C (181°F). The fans run at high speed in parallel configuration when the ECT is above 93°C (199°F).

A short to ground in the ground circuit of the fan 1 and 2 relays will cause both fans to be inoperative once the ECT reaches 93°C (199°F). This table assumes that the parallel portion of the circuit and the A/C system are functioning normally. Therefore, the malfunction is in the series portion of the circuit.

1 | Did you review the Cooling System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Engine Cooling
2 |

1. Connect a scan tool. The engine must be below operating temperature.
2. Move the blower speed switch to any position except OFF.
3. Depress the A/C switch to the ON position.
4. Use the scan tool to command the A/C compressor clutch (MG) relay ON. When the MG relay is energized the cooling fans will also turn on at low speed.

Do the cooling fans operate at low speed?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 | Exchange the fan 3 relay with a known good relay (the fan 1 relay, the A/C MG relay or the horn relay). Do the cooling fans operate at low speed? | Go to Step 8 | Go to Step 4
4 | Test the fan 3 relay coil supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 5
5 | Test the fan 3 relay coil ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6
6 | Test the circuit between the fan 3 relay and the 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 9 | Go to Step 7
7 | Test the fan 3 relay switch supply voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | --
8 | Replace the fan 3 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 9 | --
9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3