For 1990-2009 cars

Table 1: | Reference Table

#### Reference Table

Symptom | Causes
--- | ---
Main fan always ON |

• | Faulty fan 1 relay

• | Open in the fan 1 relay coil ground circuit

• | Short to voltage in the main fan motor supply voltage circuit

Auxiliary fan always ON |

• | Faulty fan 2 relay

• | Short to ground in the auxiliary fan motor ground circuit

Both fans always ON |

• | Faulty fan 3 relay

• | Faulty A/C MG relay

• | Open in the fan 2 relay coil ground circuit

• | Short to voltage in the fan 3 relay coil supply voltage circuit

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

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).

An open in the ground circuit of the A/C fan 1 and 2 relays will cause both fans to operate at high speed when the ECT is below 93°C (199°F). This table assumes that the main fan motor and/or the auxiliary fan motor runs continuously with the ignition switch in the RUN position and the ECT below 93°C (199°F).

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. Ensure that the ECT is below 93°C (199°F).
2. Depress the A/C switch to the OFF position.
3. Turn the blower switch to the OFF position.
4. Turn the ignition switch to the RUN position.

Is only the main fan motor running continuously?

Go to Step 5

Go to Step 3

3 | Is only the auxiliary fan motor running continuously? | Go to Step 9 | Go to Step 4
4 | Are both fan motors running continuously? | Go to Step 12 | Go to Step 1
5 | Remove the fan 1 relay from fuse and relay block 1. Does the main fan motor run? | Go to Step 6 | Go to Step 7
6 | Repair the short to voltage in the main fan motor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | --
7 | Test the fan 1 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 18 | Go to Step 8
8 | Replace the fan 1 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | --
9 | Remove the fan 2 relay from fuse and relay block 2. Does the auxiliary fan motor run? | Go to Step 10 | Go to Step 11
10 | Repair the short to ground in the circuit between the auxiliary fan motor and fuse and relay block 2. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | --
11 | Replace the fan 2 relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | --
12 | Remove the fan 3 relay from fuse and relay block 2. Do both fan motors run? | Go to Step 13 | Go to Step 15
13 | Test the fan 2 relay control circuit, including the A/C refrigerant pressure switch, for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 14
14 |

1. Inspect the ECT sensor for incorrect performance or for an incorrect input to the PCM. Refer to DTC P0115 or DTC P0116 in Engine Controls.
2. If the ECT sensor is operating correctly, replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls.

Did you find and correct the condition?

Go to Step 18

--

15 |

1. Test the A/C MG relay for continuity between terminals 3 and 5. Refer to Circuit Testing and Power and Grounding Component Views in Wiring Systems.
2. Test the fan 3 relay for continuity between terminals 3 and 5. Refer to Circuit Testing and Power and Grounding Component Views in Wiring Systems.

Does continuity exist in either relay?

Go to Step 16

Go to Step 17

16 | Replace the faulty relay. Refer to Cooling Fan Relay Replacement . Did you complete the replacement? | Go to Step 18 | --
17 | Repair the short to voltage in the fan 3 relay coil supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | --
18 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3