For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: Air does not flow correctly from the air distribution outlets.
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Place the blower motor switch in each speed position. Does the blower motor operate in each speed position? | Go to Step 3 | Go to Blower Motor Malfunction
3 | Are all of the HVAC control assembly controls except for the blower motor inoperative? | Go to Step 13 | Go to Step 4
4 |

1. Place the blower motor switch in the maximum speed position.
2. Place the mode switch in the vent position.
3. Place the recirculation switch in the ON position.
4. Observe the recirculation door.
5. Place the outside air switch in the ON position.

Does the recirculation door move from the recirculation to the outside air position?

Go to Step 5

Go to Air Recirculation Malfunction

5 |

1. Place the blower motor switch in the maximum speed position.
2. Place the mode switch in each mode position.

Does air flow sufficiently from the proper air distribution outlets for each selected mode position?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 6

6 | Inspect the air delivery system for the following conditions:

• | A dirty HVAC air filter, if applicable

• | An obstruction to the airflow

• | Air leaks

• | Misaligned air ducts

Did you find and correct the condition?

Go to Step 19

Go to Step 7

7 | Inspect the mode door and the mode actuator for the following conditions:

• | A misaligned mode actuator--Refer to Mode Actuator Replacement .

• | Broken or binding linkages or mode door

• | An obstruction that prevents the mode actuator from operating within the full range of motion

• | Missing seals to the mode door

• | Misaligned seals to the mode door

Did you find and correct the condition?

Go to Step 19

Go to Step 8

8 | Test the position signal circuit of the mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 9
9 | Test the low reference circuit of the mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 10
10 | Test the 5-volt reference circuit of the appropriate mode actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 11
11 |

1. Turn OFF the ignition.
2. Reconnect the mode actuator.
3. Turn ON the ignition with the engine OFF.
4. Connect a test lamp between mode door control A and mode door control B circuits of the mode actuator connector.
5. Place the mode switch in the Defrost position.
6. Place the mode switch in the Panel position.

Does the test lamp illuminate in both positions?

Go to Step 15

Go to Step 12

12 | Test the mode door control A and mode door control B circuits of the mode actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 16
13 | Test the voltage circuits of the HVAC control assembly for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 14
14 | Test the ground circuit of the HVAC control assembly for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 16
15 | Inspect for bad connections at the harness connector of the mode actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 17
16 | Inspect for bad connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 19 | Go to Step 18
17 | Replace the mode actuator. Refer to Mode Actuator Replacement . Did you complete the replacement? | Go to Step 19 | --
18 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | Go to Step 19 | --
19 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 6