For 1990-2009 cars

## Heat Excessive Heater Mode

Step | Action | Yes | No
--- | --- | --- | ---
1 | Turn the blower speed to the following settings with the ignition switch in the ON position:

1. From OFF to LOW
2. To MEDIUM 1
3. To MEDIUM 2
4. To HIGH
5. Back to OFF

Does the blower motor speed increase at each speed level when the blower speed is turned towards HIGH? and decrease as the switch is turned towards LOW?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2 |

1. Set the mode control to the HEAT position.
2. Set the blower speed to HIGH.
3. Set the temperature control to the hottest position.
4. Turn the ignition switch to ON.
5. Inspect for airflow out of the heater outlet.

Is there high airflow from the heater outlet?

Go to Step 3

Go to Step 4

3 |

1. Inspect the temperature control cable and linkages.
2. Adjust the temperature control cable. Refer to Temperature Control Cable Adjustment .

Is the repair complete?

Go to Function Test

--

4 |

1. Inspect the mode control cable and linkages.
2. Adjust the mode control cable. Refer to Mode Control Cable Adjustment .

Is the repair complete?

Go to Function Test

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## Heat Excessive Vent Mode

Step | Action | Yes | No
--- | --- | --- | ---
1 |

1. Turn the ignition switch to LOCK.
2. Move the temperature control to the hottest position, then rapidly to the coldest position.

Do you hear the temperature door slamming at each end of the door's travel?

Go to Step 2

Go to Step 4

2 |

1. Set the mode control to the VENT position.
2. Set the blower speed to HIGH.
3. Set the temperature control to the coldest position.
4. Start the engine.
5. Let the engine warm-up.
6. Measure the air temperature at the blower inlet (cowl) with a thermometer.
7. Measure the air temperature at the vent outlet with a thermometer.
8. The temperature difference should be less than 5°C (10°F).

Is the temperature difference 5°C (10°F) or greater?

Go to Step 3

Go to Function Test

3 |

• | Inspect for hot air leaks from the engine compartment to the blower air inlet.

• | Inspect the heater case for leaks.

• | Repair as necessary. Refer to Heater Case Replacement .

Is the repair complete?

Go to Function Test

--

4 |

1. Inspect the temperature control cable and linkages.
2. Adjust the temperature control cable. Refer to Temperature Control Cable Adjustment .

Is the repair complete?

Go to Function Test

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