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Makes 🢒 GMC_Truck 🢒 2004 🢒 Savana 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Too Cold in Vehicle - Auxiliary

Too Cold in Vehicle - Auxiliary Passenger Van w/Aux

Test Description

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

  1. This checks for proper cooling system operation.

    2.

  2. This check for proper air temperature actuator movement.

    3.

  3. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

    4.

  4. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

    5.

  5. The auxiliary blower motor switch control circuit should not have continuity to ground when front auxiliary HVAC control assembly is in any position except REAR CNTL.

    6.

  6. The voltage will vary between 0-12 volts during normal operation. The rear auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the rear auxiliary HVAC control assembly.

    7.

  7. This step checks complete auxiliary air temperature door control circuit from the front HVAC control assembly to the auxiliary HVAC control processor to the auxiliary air temperature actuator.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient.

1

Did you review the HVAC operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2
  1. Turn ON the ignition, with the engine OFF.
  2. Place the mode switch in any position except OFF.
  3. Place the auxiliary blower control in each speed position.

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

--

Go to Step 3

Go to Auxiliary Blower Motor Inoperative

3

Does the auxiliary blower motor operate correctly for each speed position?

--

Go to Step 4

Go to Auxiliary Blower Motor Malfunction

4

Inspect the cooling system for the following:

    • A low coolant level
    • A loose or worn accessory drive belt
    • A leaking radiator hose or heater hoses
    • A kinked radiator hose or heater hoses
    • A missing radiator cap pressure seal
    • A leaking radiator cap

Did you find and correct the condition?

--

Go to Step 37

Go to Step 5

5
  1. Start the engine.
  2. Place the mode switch in the OFF, VENT or HEAT positions.

Does the A/C compressor operate?

--

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 6

6

Does the Auxiliary Too Cold in Vehicle condition happen with front and rear auxiliary HVAC control assemblies?

--

Go to Step 9

Go to Step 7

7

Does the Auxiliary Too Cold in Vehicle condition happen with front auxiliary HVAC control assembly?

--

Go to Step 13

Go to Step 8

8

Does the Auxiliary Too Cold in Vehicle condition happen with rear HVAC control assembly?

--

Go to Step 16

Go to Too Cold in Vehicle

9

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the auxiliary air temperature actuator.
  3. Place the front auxiliary air temperature switch from the coldest position to the warmest position.

Does the air temperature actuator move with a smooth transition between COLD and HOT?

--

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

Go to Step 10

10

  1. Disconnect the auxiliary air temperature actuator.
  2. Place the blower motor switch on the front auxiliary HVAC control assembly to any position except REAR CNTL or OFF.
  3. Place the front auxiliary air temperature switch from the coldest position to the warmest position.
  4. Measure the voltage from the auxiliary air temperature door control circuit of the auxiliary air temperature actuator to a good ground.

Does the voltage measure within the specified values with a smooth transition between COLD and HOT?

0-12 V

Go to Step 11

Go to Step 20

11

Connect a test lamp between the ignition 3 voltage circuit and ground circuit of the auxiliary air temperature actuator.

Does the test lamp illuminate?

--

Go to Step 19

Go to Step 12

12

Connect a test lamp between the ignition 3 voltage circuit and good ground.

Does the test lamp illuminate?

--

Go to Step 21

Go to Step 22

13

  1. Disconnect the auxiliary HVAC control processor.
  2. Place the blower motor switch on the front auxiliary HVAC control assembly to any position except REAR CNTL or OFF.
  3. Place the front auxiliary air temperature switch from the coldest position to the warmest position.
  4. Measure the voltage from the front auxiliary HVAC control assembly on the auxiliary air temperature door control circuit to a good ground.

Does the voltage measure within the specified values with a smooth transition between COLD and HOT?

0-12 V

Go to Step 14

Go to Step 23

14

  1. Place the blower motor switch on the front auxiliary HVAC control assembly to any position except REAR CNTL or OFF.
  2. Connect a test lamp between the ignition 3 voltage circuit of the front HVAC control assembly and auxiliary blower motor switch control circuit to the front auxiliary HVAC control assembly.

Does the test lamp illuminate?

--

Go to Step 24

Go to Step 15

15

Connect a test lamp between the ignition 3 voltage circuit and good ground .

Does the test lamp illuminate?

--

Go to Step 30

Go to Step 25

16

  1. Disconnect auxiliary HVAC control processor.
  2. Place the blower motor switch on the front auxiliary HVAC control assembly to the REAR CNTL position.
  3. Place the rear auxiliary air temperature switch from the coldest position to the warmest position.
  4. Measure the voltage from the rear auxiliary HVAC control assembly to the auxiliary air temperature door control circuit to a good ground.

Does the voltage measure within the specified values with a smooth transition between COLD and HOT?

0-12 V

Go to Step 17

Go to Step 26

17
  1. Place the blower motor switch on the front auxiliary HVAC control assembly to the REAR CNTL position.
  2. Connect a test lamp between the ignition 3 voltage circuit of the rear HVAC control assembly and auxiliary blower motor switch control circuit to the front auxiliary HVAC control assembly.

Does the test lamp illuminate?

--

Go to Step 25

Go to Step 18

18

Connect a test lamp between the ignition 3 voltage circuit of the rear auxiliary HVAC control assembly and good ground.

Does the test lamp illuminate?

--

Go to Step 27

Go to Step 28

19

Inspect the auxiliary air temperature door and the auxiliary air temperature actuator for the following conditions:

    • Misaligned auxiliary air temperature actuator.
    • Broken or binding linkages or air temperature door
    • Obstruction that prevents the air temperature door from operating within it's full range of motion
    • Missing seals to the auxiliary air temperature door
    • Misaligned seals to the auxiliary air temperature door

Did you find and correct the condition?

--

Go to Step 37

Go to Step 29

20

Test the auxiliary air temperature door control circuit of the auxiliary air temperature actuator from the front auxiliary HVAC control assembly to the auxiliary air temperature actuator for an open, high resistance, short to ground, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 25

21

Test the ground circuit of the auxiliary air temperature 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 37

Go to Step 29

22

Test the ignition 3 voltage circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 29

23

Test the auxiliary air temperature door control circuit of the auxiliary air temperature actuator from the front auxiliary HVAC control assembly to the auxiliary HVAC control processor for an open, high resistance, short to ground, and short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 30

24

Test the auxiliary blower motor switch control circuit for short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 30

25

Test the ignition 3 voltage circuit of the auxiliary HVAC control processor for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 32

26

Test the auxiliary air temperature door control circuit of the auxiliary air temperature actuator from the rear auxiliary HVAC control assembly to the auxiliary HVAC control processor for an open, high resistance, short to ground, and short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 31

27

Test the auxiliary blower motor switch control circuit 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 37

Go to Step 31

28

Test the ignition 3 voltage circuit of the rear auxiliary HVAC control assembly for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 37

Go to Step 31

29

Inspect for poor connections at the harness connector of the auxiliary air temperature 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 37

Go to Step 33

30

Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. 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 37

Go to Step 34

31

Inspect for poor connections at the harness connector of the rear auxiliary HVAC control assembly. 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 37

Go to Step 35

32

Inspect for poor connections at the harness connector of the auxiliary HVAC control processor. 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 37

Go to Step 36

33

Replace the auxiliary air temperature actuator. Refer to Auxiliary Temperature Valve Actuator Replacement .

Did you complete the replacement?

--

Go to Step 37

--

34

Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front .

Did you complete the replacement?

--

Go to Step 37

--

35

Replace the rear auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Rear .

Did you complete the replacement?

--

Go to Step 37

--

36

Replace the auxiliary HVAC control processor. Refer to Auxiliary HVAC Control Processor Replacement .

Did you complete the replacement?

--

Go to Step 37

--

37

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

Too Cold in Vehicle - Auxiliary Cargo Van w/Aux

Test Description

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

  1. This checks for proper cooling system operation.

    2.

  2. The voltage will vary between 0-12 volts during normal operation. The front auxiliary HVAC control assembly connector must be connected during this step. This checks for proper operation of the air temperature actuator door control circuit and the front auxiliary HVAC control assembly.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient.

1

Did you review the HVAC operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2
  1. Turn ON the ignition, with the engine OFF.
  2. Place the auxiliary mode switch in any position except OFF.
  3. Place the auxiliary blower control in each speed position.

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

--

Go to Step 3

Go to Auxiliary Blower Motor Inoperative

3

Does the auxiliary blower motor operate correctly for each speed position?

--

Go to Step 4

Go to Auxiliary Blower Motor Malfunction

4

Inspect the cooling system for the following:

    • A low coolant level
    • A loose or worn accessory drive belt
    • A leaking radiator hose or heater hoses
    • A kinked radiator hose or heater hoses
    • A missing radiator cap pressure seal
    • A leaking radiator cap

Did you find and correct the condition?

--

Go to Step 17

Go to Step 5

5
  1. Start the engine.
  2. Place the mode switch in the OFF, VENT or HEAT positions.

Does the A/C compressor operate?

--

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 6

6
  1. Observe the drive shaft of the auxiliary air temperature actuator.
  2. Place the auxiliary air temperature switch from the coldest position to the warmest position.

Does the auxiliary air temperature actuator drive shaft rotate at all?

--

Go to Step 7

Go to Step 8

7

Inspect the auxiliary air temperature door and the auxiliary air temperature actuator for the following conditions:

    • Misaligned auxiliary air temperature actuator.
    • Broken or binding linkages or auxiliary air temperature door
    • Obstruction that prevents the auxiliary air temperature door from operating within it's full range of motion
    • Missing seals to the auxiliary air temperature door
    • Misaligned seals to the auxiliary air temperature door

Did you find and correct the condition?

--

Go to Step 17

Go to Step 8

8

Test the ignition 3 voltage circuit of the auxiliary air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 9

9

Test the ground circuit of the auxiliary air temperature actuator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 10

10

Test the auxiliary air temperature door control circuit of the auxiliary air temperature actuator for an open, high resistance, short to ground, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 11

11

Important:: The front auxiliary HVAC control assembly connector must be connected to correctly perform this test.

  1. Turn ON the ignition, with the engine OFF.
  2. Measure the voltage from the auxiliary air temperature door position signal circuit of the auxiliary air temperature actuator to a good ground.
  3. Place the auxiliary air temperature switch from the coldest position to the warmest position.

Does the voltage measure within the specified values with a smooth transition between COLD and HOT?

0-12 V

Go to Step 14

Go to Step 12

12

Inspect for poor connections at the harness connector of the auxiliary air temperature 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 17

Go to Step 13

13

Inspect the auxiliary air temperature actuator, door and any attaching linkage for binding or a condition that prevents drive shaft rotation.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

14

Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. 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 17

Go to Step 16

15

Replace the auxiliary air temperature actuator. Refer to Auxiliary Temperature Valve Actuator Replacement .

Did you complete the replacement?

--

Go to Step 17

--

16

Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front .

Did you complete the replacement?

--

Go to Step 17

--

17

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

Too Cold in Vehicle - Auxiliary Cargo Van w/Aux Rear Heater

Test Description

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

  1. This checks for proper cooling system operation. This step links to Too Cold in Vehicle because system shows no sign of concern with auxiliary heater.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient.

1

Did you review the HVAC operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2
  1. Turn ON the ignition, with the engine OFF.
  2. Place the mode switch in any position except OFF.
  3. Place the blower control in each speed position.

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

--

Go to Step 3

Go to Blower Motor Inoperative

3

Does the blower motor operate correctly for each speed position?

--

Go to Step 4

Go to Blower Motor Malfunction

4

Inspect the cooling system for the following:

    • A low coolant level
    • A loose or worn accessory drive belt
    • A leaking radiator hose or heater hoses
    • A kinked radiator hose or heater hoses
    • A missing radiator cap pressure seal
    • A leaking radiator cap

Did you find and correct the condition?

--

Go to Step 5

Go to Too Cold in Vehicle

5

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2