GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Park Avenue 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Air Delivery Improper

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

DEFINITION: Air does not flow correctly from the air distribution outlets.

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

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 in each speed position?

--

Go to Step 5

Go to Blower Motor Malfunction

5
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switch in the floor position.
  3. Alternately, place the recirculation switch in the ambient air position and the recirculation position.

Does the recirculation door operate properly?

--

Go to Step 6

Go to Air Recirculation Malfunction

6

Important:: In order to execute the HVAC Recalibration command, the scan tool disrupts keep alive memory (KAM) causing DTC B1652 (Loss of KAM) to be set as history.

  1. Install a scan tool.
  2. With a scan tool, perform the HVAC Recalibration command in Heating and Air Conditioning Special Functions.
  3. With a scan tool, observe the current DTC list in Heating and Air Conditioning.

Does the scan tool display DTC B1340, B1341, B1343, or B1344?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 7

7

Place the mode switch in each mode position, including defrost.

Does the display on the HVAC control module respond correctly to the changes in mode selection?

--

Go to Step 8

Go to Step 16

8
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switch in each mode position.
  3. Place the defrost switch in the defrost position.

Does the air flow from the correct air distribution outlets for each mode selected?

--

Go Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 9

9
  1. With a scan tool, observe the Htr./Def./A/C Dr. Commanded parameter in the Heating and Air Conditioning data list.
  2. Place the mode switch in each mode position.
  3. Place the defrost switch in the defrost position.

Does the scan tool indicate that the Htr./Def./A/C Dr. Commanded parameter changes for each change in selected mode position?

--

Go to Step 10

Go to Step 11

10
  1. Turn OFF the ignition.
  2. Disconnect the mode actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the mode door position signal circuit and the low reference circuit of the mode actuator.
  5. With a scan tool, observe the Htr./Def./A/C Dr. Actual parameter.

Does the scan tool indicate that the Htr./Def./A/C Dr. Actual parameter is less than the specified value?

4 Counts

Go to Step 13

Go to Step 11

11

Test the mode door position signal circuit of the mode actuator for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 12

12

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

Did you find and correct the condition?

--

Go to Step 21

Go to Step 17

13

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 21

Go to Step 14

14

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
    • A broken or binding mode door
    • An obstruction that prevents the mode door from operating within it's full range of motion

Did you find and correct the condition?

--

Go to Step 21

Go to Step 15

15

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 21

Go to Step 18

16

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 21

Go to Step 19

17

Inspect for poor connections at the harness connector of the instrument panel integration module (IPM). 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 21

Go to Step 20

18

Important: Perform the recalibration procedure for the mode actuator.

Replace the mode actuator. Refer to Mode Actuator Replacement .

Did you complete the replacement?

--

Go to Step 21

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19

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

Did you complete the replacement?

--

Go to Step 21

--

20

Important: Perform the recalibration procedure for the IPM.

Replace the IPM. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 21

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21

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2