For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Set the mode switch to the floor position. Is there too much heat when the mode switch is in the floor position? | Go to Step 3 | Go to Step 4
3 | Check for defroster bleed. Is there objectionable defroster bleed? | Go to Step 5 | Go to Step 6
4 |

1. Check the door travel, the cables, the controls, and the linkage for the heater and the defroster.
2. Adjust or repair, as required.

Is the repair complete?

System OK

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5 |

1. In vehicles equipped with A/C, set the A/C switch to OFF.
2. In all vehicles, set the blower speed to 4.
3. Set the temperature to full hot.
4. Turn the ignition switch to ON.
5. Check for airflow from the floor outlets.
6. Check the floor outlet attachment.

Is the airflow high?

Go to Step 7

Go to Step 8

6 | Check for a change in the airflow at different blower speeds. Does the airflow change as the setting for the blower-speed switch is changed? | System OK | Go to Blower Motor Malfunction
7 |

1. Check the temperature door travel, the cables, and the linkage.
2. Adjust to full cold.
3. Check for full hot.

Is the repair complete?

System OK

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8 | Adjust or repair the floor/defroster and/or the vent/floor mode. Is the repair complete? | System OK | Go to Step 9
9 | Set the mode switch to the vent position. In the vent position, is the problem objectionable bleed? | Go to Step 10 | Go to Step 15
10 |

1. Check the system case for leaks.
2. Check the floor outlet attachment.

Are any problems found?

Go to Step 11

Go to Step 12

11 | Repair the system case or the floor outlet attachment as required. Is the repair complete? | System OK | Go to Step 12
12 |

1. Turn the ignition switch OFF.
2. Turn the temperature control knob to full hot, then rapidly to full cold.

Do you hear the door slam just before you reach the end of the control travel?

Go to Step 13

Go to Step 14

13 | Adjust the vent door to vent more. Is the repair complete? | System OK | --
14 |

1. Check the temperature door travel, the cables, and the linkage.
2. Verify that the temperature door goes to full cold.
3. Check the temperature door for full hot.

Is the temperature door travel correct?

System OK

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15 |

1. Set the fresh air/recirculating air control to fresh air.
2. Set the temperature control to full cold.
3. Start the vehicle and allow the engine to warm up.
4. Measure the air temperature at the blower inlet, and at the vent air outlet inside the vehicle.

Is the outlet air more than 5°C (9°F) warmer than the inlet air?

Go to Step 16

System OK

16 |

1. Check for hot air leaks from the engine compartment to the blower inlet.
2. Repair as needed.

Is the repair complete?

System OK

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