GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The auxiliary mode doors cannot be adjusted.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

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 Auxiliary Blower Motor Always On

3

  1. Turn ON the ignition, with the engine OFF.
  2. Place the front auxiliary blower motor switch in each speed position.

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

Go to Step 4

Go to Auxiliary Blower Motor Inoperative

4

Does the auxiliary blower motor operate at the desired speed?

Go to Step 5

Go to Auxiliary Blower Motor Malfunction

5

  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch ON.
  3. Place the mode switch from the floor position to the upper outlets position.
  4. With a scan tool, observe the Auxiliary Mode Door Commanded parameter in the HVAC data list.

Does the Auxiliary Mode Door Commanded parameter count value change?

Go to Step 8

Go to Step 6

6

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

Did you find and correct the condition?

Go to Step 8

Go to Step 7

7

Replace the auxiliary HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2