GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2008 🢒 LaCrosse 🢒 HVAC 🢒 HVAC - Manual 🢒 Noise Diagnosis - HVAC Module

Step

Action

Yes

No

DEFINITION: Noise originating from the HVAC module.

1

Were you sent here from Symptoms or another diagnostic table?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

or

Go to Symptoms - HVAC Systems - Automatic

2
  1. Start the engine.
  2. Cycle through all of the following:
    3. • Blower motor speeds
    • HVAC modes
    • Temperature control settings
  3. Determine the type of noise:
    4. • Scrape, Chirping or groaning
    • Tick/click or Pop
    • Air rush/whistle

Is a tick/click, chirping, groaning, air rush/whistle or scraping noise present, but decreases as blower motor speed is decreased?

Go to Noise Diagnosis - Blower Motor

Go to Step 3

3

Is a scrape, chirping, or groaning noise evident when selecting modes or temperature settings?

Go to Step 8

Go to Step 4

4

Is a tick/click or pop noise present?

Go to Step 5

Go to Step 6

5

Inspect any visible or easily accessible actuators.

Are the actuators operating properly?

Go to Step 9

Go to Step 14

6

Is a air rush/whistle noise evident in all modes, but not all temperature settings?

Go to Step 9

Go to Step 7

7

Is an air rush/ whistle noise evident only in defrost or floor mode?

Go to Step 8

Go to Step 1

8

Inspect any visible or easily accessible ducts for obstructions or foreign materials.

    • Air Inlet
    • Defroster Vent
    • Panel Vents
    • Floor Vents

Were any obstructions or foreign materials found?

Go to Step 12

Go to Step 9

9

Remove the lower trim panel. Refer to Instrument Panel Trim Pad Replacement .

  1. Inspect the ducts for obstructions or foreign materials.
  2. Inspect the HVAC module for obstructions or foreign materials.

Is the repair complete?

Go to Step 12

Go to Step 10

10

Inspect the mode valve assembly, temperature doors, and air inlet door for the following conditions.

    • Warping
    • Cracking
    • Sticking
    • Ripped seals

Did you find any of these conditions?

Go to Step 11

Go to Step 13

11

Replace the appropriate door and/or seal.

Is the action complete?

Go to Step 15

--

12

Remove any obstructions or foreign materials found.

Is the action complete?

Go to Step 15

--

13

Inspect the mode, temperature, and air inlet door actuators.

Are the actuators operating properly?

Go to Step 15

Go to Step 14

14

Replace appropriate actuator.

Is the action complete?

Go to Step 15

--

15

If removed, install the lower trim panel. Refer to Instrument Panel Trim Pad Replacement .

Is the action complete?

Go to Step 16

--

16

Operate the system to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2