GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Montana 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Delivery Improper - Auxiliary

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

DEFINITION: Air does not flow correctly from the auxiliary 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 - Manual

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

Is the auxiliary blower motor OFF?

--

Go to Step 3

Go to Auxiliary Blower Motor Always On

3
  1. Place the front auxiliary blower motor switch in the rear control position.
  2. Place the rear auxiliary blower motor switch in the OFF position.

Is the auxiliary blower motor OFF?

--

Go to Step 4

Go to Auxiliary Blower Motor Always On

4

Place the front auxiliary blower motor switch in each speed position.

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

--

Go to Step 5

Go to Auxiliary Blower Motor Inoperative

5

Does the auxiliary blower motor operate at the desired speeds?

--

Go to Step 6

Go to Auxiliary Blower Motor Malfunction

6
  1. Place the front auxiliary blower motor switch in the rear control position.
  2. Place the rear auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor operate at the desired speeds?

--

Go to Step 7

Go to Auxiliary Blower Motor Malfunction

7
  1. Place the front auxiliary blower motor switch in the maximum speed position.
  2. Place the mode switch in the floor position.

Does air flow from the auxiliary floor outlets?

--

Go to Step 8

Go to Step 9

8

Place the mode switch in the vent position.

Does air flow from the upper auxiliary outlets?

--

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

Go to Step 9

9
  1. Turn OFF the ignition.
  2. Disconnect the auxiliary mode actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 3 voltage circuit of the auxiliary 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 18

10

Test the ground circuit of the auxiliary 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 21

Go to Step 11

11
  1. Connect the auxiliary mode actuator.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage of the auxiliary mode door control circuit of the auxiliary mode actuator to a good ground at pin 6 of the auxiliary mode door control circuit.
  4. Place the mode switch in the vent position.

Does the voltage measure within the specified range?

10-12 V

Go to Step 12

Go to Step 13

12

Place the mode switch in the floor position.

Does the voltage measure near the specified value?

0 V

Go to Step 15

Go to Step 14

13

Test the auxiliary mode door control circuit of the auxiliary mode actuator for an open or short to ground. 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

14

Test the auxiliary mode door control circuit of the auxiliary mode actuator for a short to voltage. 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

15

Inspect the auxiliary mode door and actuator for the following conditions:

    • A misaligned auxiliary mode actuator. Refer to Auxiliary Mode Valve Actuator Replacement
    • Broken or binding linkages
    • An obstruction that prevents the auxiliary mode door 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 21

Go to Step 16

16

Inspect for poor connections at the harness connector of the auxiliary 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 19

17

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 20

18

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

Did you complete the repair?

--

Go to Step 21

--

19

Replace the auxiliary mode actuator. Refer to Auxiliary Mode Valve Actuator Replacement .

Did you complete the replacement?

--

Go to Step 21

--

20

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

Did you complete the replacement?

--

Go to Step 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3