Verify the customer complaint.

Are the customer concerns verified?

Go to Step 2

System OK

Is there too much heat when the mode switch is in floor position?

Go to Step 3

Go to Step 9

Is there objectionable defroster bleed?

Go to Step 4

Go to Step 5

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

Is the airflow high?

Go to Step 6

Go to Step 8

Check for a change in the airflow at different blower speeds.

Does the airflow change as the setting for the blower-speed switch is scanned?

Go to Step 7

Go to Air Delivery Improper

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

Is the repair complete?

System OK

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Adjust or repair the floor/defroster and/or the vent/floor mode.

Is the repair complete?

System OK

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In the vent position, is the problem objectionable bleed?

Go to Step 10

Go to Step 15

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

Are there problems?

Go to Step 11

Go to Step 12

Repair the system case or the floor outlet attachment as required.

Is the repair complete?

System OK

Go to Step 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

Adjust the vent door to vent more.

Is the repair complete?

System OK

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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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1. Set the fresh air/recirculating air control to fresh air (indicator lamp off).
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, or cowl, and at the vent air outlet inside the vehicle.

Is the outlet air more than 5°C (41°F) warmer than the inlet air?

Go to Step 16

System OK

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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