GM Service Manual Online
For 1990-2009 cars only

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 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
  4. Determine the type of noise:
  5. • Scrape, pop
    • Tick/click, chirp or groaning
    • Air rush/whistle

Is a scrape or pop noise evident when selecting modes or temperature settings?

Go to Step 6

Go to Step 3

3

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

Go to Step 6

Go to Step 4

4

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

Go to Step 6

Go to Step 5

5

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

Go to Step 6

Go to Step 6

6

  1. Remove the instrument panel center trim bezel. Refer to Instrument Panel Accessory Bezel Replacement .
  2. Remove the center air outlet duct.

Is the action complete?

Go to Step 7

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7

  1. Inspect the air flow doors for proper operation.
  2. Inspect the ducts for obstructions or foreign materials.

Were any of these conditions found?

Go to Step 10

Go to Step 8

8

Inspect the mode and temperature doors and seals for warping or cracking.

Are the doors in normal condition?

Go to Step 11

Go to Step 9

9

Replace the appropriate door and/or seals.

Is the repair complete?

Go to Step 11

--

10

Remove any obstructions or foreign material found.

Is the action complete?

Go to Step 11

--

11

  1. Install the center air outlet duct.
  2. Install the I/P center trim bezel. Refer to Instrument Panel Accessory Bezel Replacement .

Is the action complete?

Go to Step 12

--

12

Operate the system to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2