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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Bonneville 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Delivery Improper

Diagnostic Aids

To prevent evaporator freezing, the recirc door periodically rotates back and forth from the outside air to recirc position. The tone of the blower and the velocity of the air speed may be noticeably different when the recirc actuator switches positions. This is a normal condition. If excessive air speed change is noticed inspect the cabin air filter for contamination or blockage.

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 HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

2
  1. Turn ON the ignition, with the engine OFF.
  2. Turn OFF the HVAC controls.

Is the blower motor OFF?

Go to Step 3

Go to Blower Motor Always On

3

Place the blower motor switch in each speed position.

Does the blower motor operate in any of the speed positions?

Go to Step 4

Go to Blower Motor Inoperative

4

Does the blower motor operate at the desired speeds?

Go to Step 5

Go to Blower Motor Malfunction

5
  1. Place the blower motor switch in the maximum speed position.
  2. Place the bi-level switch in the ON position.
  3. Place the recirculation switch in the recirculation and ambient air positions.

Does the recirculation door operate correctly?

Go to Step 6

Go to Air Recirculation Malfunction

6
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switches in each mode position.

Does the air flow from the proper air distribution outlets in each mode position?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 7

7

Inspect the air delivery system for the following conditions:

    • A dirty HVAC air filter, if applicable
    • An obstruction to the air flow
    • Air leaks
    • Misaligned air ducts

Did you find and correct the condition?

Go to Step 18

Go to Step 8

8

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 its 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 18

Go to Step 9

9
  1. Turn OFF the ignition.
  2. Disconnect the mode actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 3 voltage circuit of the mode actuator with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 15

10

Test the low reference circuit of the mode actuator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 11

11
  1. Measure the voltage from the mode door control circuit of the mode actuator to a good ground.
  2. Place the mode switches in each mode position.

Does the measured voltage change for each change in selected mode position?

Go to Step 13

Go to Step 12

12

Test the mode door control circuit of the mode actuator for an open, high resistance, short to ground, or short to voltage. 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

13

Inspect for poor connections at the harness connector of the mode actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

14

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

15

Repair the ignition 3 voltage circuit of the mode actuator. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

16

Replace the mode actuator. Refer to Mode Actuator Replacement .

Did you complete the replacement?

Go to Step 18

--

17

Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 7