GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Catera 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Air Delivery Improper

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests to ensure that the heater and A/C control has the ability to command the inside air valve actuator.

    2.

  2. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    3.

  3. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    4.

  4. Ensures the heater and A/C control has the ability to control the inside air valve actuator.

    5.

  5. Ensures the heater and A/C control has the ability to control the inside air valve actuator.

    6.

  6. Ensures the heater and A/C control has the ability to control the inside air valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

    7.

  7. Ensures the heater and A/C control has the ability to control the inside air valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

    8.

  8. Tests to ensure that the heater and A/C control has the ability to command the mode valve actuator.

    9.

  9. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    10.

  10. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    11.

  11. Ensures the heater and A/C control has the ability to control the mode valve actuator.

    12.

  12. Ensures the heater and A/C control has the ability to control the mode valve actuator.

    13.

  13. Ensures the heater and A/C control has the ability to control the mode valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

    14.

  14. Ensures the heater and A/C control has the ability to control the mode valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

    15.

  15. Tests to ensure that the heater and A/C control has the ability to command the defrost valve actuator.

    16.

  16. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    17.

  17. Tests for the proper operation of the circuit in the high voltage range when the actuator is at rest.

    18.

  18. Ensures the heater and A/C control has the ability to control the defrost valve actuator.

    19.

  19. Ensures the heater and A/C control has the ability to control the defrost valve actuator.

    20.

  20. Ensures the heater and A/C control has the ability to control the defrost valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

    21.

  21. Ensures the heater and A/C control has the ability to control the defrost valve actuator. Test lamp will be illuminated when connection made. Test lamp should increase intensity when commanded.

Step

Action

Values

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?

--

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 heater and A/C control.

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 each speed position?

--

Go to Step 4

Go to Blower Motor Inoperative

4
  1. Start the engine.
  2. Place the mode switch in the vent position.
  3. Place the blower motor switch in the maximum speed position.
  4. Place the recirculation switch in the ON position.

Does the recirculation door operate properly?

--

Go to Step 5

Go to Air Recirculation Malfunction

5

Inspect the air distribution system for the following conditions:

    • A restricted passenger compartment air filter
    • An obstruction restricting air flow
    • Air leaks
    • Misaligned air ducts

Did you find and correct the condition?

--

Go to Step 57

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Turn ON the ignition, with the engine OFF.
  3. Install a scan tool.
  4. With a scan tool, observe the Mode Up Switch and the Mode Down Switch parameters in the Heater and Air Conditioning data list.
  5. Place the mode switch in each mode position.

Does the Mode Up Switch and the Mode Down Switch parameters go Active with each change of switch position?

--

Go to Step 7

Go to Step 43

7

With a scan tool, command the Int. Air Mix Door Mot. ON and OFF.

Does the scan tool indicate that the Int. Air Mix Door Mot. parameter stay Inactive when the door is commanded?

--

Go to Step 43

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Disconnect the inside air valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the B+ power supply voltages at the inside air valve actuator connector to a good ground.

Does the voltage measure near the specified value?

12.5 V

Go to Step 9

Go to Step 45

9

Important: Ensure the connector for the inside air valve actuator is connected during this step to avoid misdiagnosis.

  1. Turn OFF the ignition.
  2. Connect inside air valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure voltage on terminals 3 and 6 at the inside air valve actuator to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 10

Go to Step 46

10

Important: Ensure the connector for the inside air valve actuator is connected during this step to avoid misdiagnosis.

Measure voltage on terminals 1 and 4 at the inside air valve actuator.

Does the voltage measure near the specified value?

0.5 V

Go to Step 11

Go to Step 47

11

  1. Turn OFF the ignition.
  2. Disconnect the inside air valve actuator.
  3. Connect test lamp from terminal 2 to terminal 1 of the inside air valve actuator.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the Int. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 12

Go to Step 48

12

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 4 of the inside air valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Int. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 13

Go to Step 49

13

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 2 to terminal 3 of the inside air valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Int. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 14

Go to Step 50

14

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 6 of the inside air valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Int. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 15

Go to Step 51

15
  1. Disconnect the inside air valve actuator.
  2. Measure the resistance from terminal 2 to terminal 1 of the inside air valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 16

Go to Step 53

16

Measure the resistance from terminal 2 to terminal 3 of the inside air valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 17

Go to Step 53

17

Measure the resistance from terminal 5 to terminal 4 of the inside air valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 18

Go to Step 53

18

Measure the resistance from terminal 5 to terminal 6 of the inside air valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 19

Go to Step 53

19

With a scan tool, command the Flr. Air Mix Door Mot. ON and OFF.

Does the scan tool indicate that the Flr. Air Mix Door Mot. parameter stay Inactive when the door is commanded?

--

Go to Step 43

Go to Step 20

20
  1. Turn OFF the ignition.
  2. Disconnect the mode valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the B+ power supply voltages at the mode valve actuator connector to a good ground.

Does the voltage measure near the specified value?

12.5 V

Go to Step 21

Go to Step 45

21

Important: Ensure the connector for the mode valve actuator is connected during this step to avoid misdiagnosis.

  1. Turn OFF the ignition.
  2. Connect mode valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure voltage on terminals 3 and 6 at the mode valve actuator to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 22

Go to Step 46

22

Important: Ensure the connector for the mode valve actuator is connected during this step to avoid misdiagnosis.

Measure voltage on terminals 1 and 4 at the mode valve actuator.

Does the voltage measure near the specified value?

0.5 V

Go to Step 23

Go to Step 47

23

  1. Turn OFF the ignition.
  2. Disconnect the mode valve actuator.
  3. Connect test lamp from terminal 2 to terminal 1 of the mode valve actuator.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the Flr. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 24

Go to Step 48

24

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 4 of the mode valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Flr. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 25

Go to Step 49

25

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 2 to terminal 3 of the mode valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Flr. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 26

Go to Step 50

26

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 6 of the mode valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Flr. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 27

Go to Step 51

27
  1. Disconnect the mode valve actuator.
  2. Measure the resistance from terminal 2 to terminal 1 of the mode valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 28

Go to Step 53

28

Measure the resistance from terminal 2 to terminal 3 of the mode valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 29

Go to Step 53

29

Measure the resistance from terminal 5 to terminal 4 of the mode valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 30

Go to Step 53

30

Measure the resistance from terminal 5 to terminal 6 of the mode valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 31

Go to Step 53

31

With a scan tool, command the Def. Air Mix Door Mot. ON and OFF.

Does the scan tool indicate that the Def. Air Mix Door Mot. parameter stay Inactive when the door is commanded?

--

Go to Step 43

Go to Step 32

32
  1. Turn OFF the ignition.
  2. Disconnect the defrost valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the B+ power supply voltages at the defrost valve actuator connector to a good ground.

Does the voltage measure near the specified value?

12.5 V

Go to Step 33

Go to Step 45

33

Important: Ensure the connector for the defrost valve actuator is connected during this step to avoid misdiagnosis.

  1. Turn OFF the ignition.
  2. Connect defrost valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure voltage on terminals 3 and 6 at the defrost valve actuator to a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 34

Go to Step 46

34

Important: Ensure the connector for the defrost valve actuator is connected during this step to avoid misdiagnosis.

Measure voltage on terminals 1 and 4 at the defrost valve actuator.

Does the voltage measure near the specified value?

0.5 V

Go to Step 35

Go to Step 47

35

  1. Turn OFF the ignition.
  2. Disconnect the defrost valve actuator.
  3. Connect test lamp from terminal 2 to terminal 1 of the defrost valve actuator.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the Def. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 36

Go to Step 48

36

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 4 of the defrost valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Def. Air Mix Door Mot. ON and OFF.

Does the test lamp illuminate with each command?

--

Go to Step 37

Go to Step 49

37

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 2 to terminal 3 of the defrost valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Def. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 38

Go to Step 50

38

  1. Turn OFF the ignition.
  2. Connect test lamp from terminal 5 to terminal 6 of the defrost valve actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the Def. Air Mix Door Mot. ON and OFF.

Does the test lamp flicker when commanded?

--

Go to Step 39

Go to Step 51

39
  1. Disconnect the defroster valve actuator.
  2. Measure the resistance from terminal 2 to terminal 1 of the defrost valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 40

Go to Step 53

40

Measure the resistance from terminal 2 to terminal 3 of the defrost valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 41

Go to Step 53

41

Measure the resistance from terminal 5 to terminal 4 of the defrost valve actuator.

Does the resistance measure near specified value?

90 ohms

Go to Step 42

Go to Step 53

42

Measure the resistance from terminal 5 to terminal 6 of the defrost valve actuator.

Does the resistance measure near specified value?

90 ohms

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

Go to Step 53

43
  1. Turn OFF the ignition.
  2. Disconnect the heater and A/C control connector C1.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage on the ignition positive voltage circuit at the heater and A/C control connector.

Does the voltage measure near specified value?

12 V

Go to Step 44

Go to Step 52

44

Test the ground circuit of the heater and A/C control for 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 57

Go to Step 54

45

Test the B+ power supply circuits of the applicable valve actuator for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

46

Test circuits in terminals 3 and 6 of the applicable valve actuator for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

47

Test circuits in terminals 1 and 4 of the applicable valve actuator for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

48

Test circuit in terminal 1 of the applicable valve actuator for an open, high resistance or short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

49

Test circuit in terminal 4 of the applicable valve actuator for an open, high resistance or short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

50

Test circuit in terminal 3 of the applicable valve actuator for an open, high resistance or short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

51

Test circuit in terminal 6 of the applicable valve actuator for an open, high resistance or short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

Go to Step 54

52

Repair the ignition positive voltage circuit to the heater and A/C control. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 57

--

53

Inspect for poor connections at the harness connector of the applicable valve 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 57

Go to Step 55

54

Inspect for poor connections at the harness connector of the heater and A/C control. 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 57

Go to Step 56

55

Replace the applicable valve actuator. Refer to one of the following procedures:

Did you complete the replacement?

--

Go to Step 57

--

56

Important: Perform the recalibration procedure for the heater and A/C control.

Replace the heater and A/C control. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

--

Go to Step 57

--

57

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2