GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Spark 🢒 HVAC 🢒 HVAC - Manual 🢒 Too Cold in Vehicle

Step

Action

Yes

No

1

Verify the customer's complaint.

Are the customer's concerns verified?

Go to Step 2

System OK

2

Inspect the coolant level.

Is the coolant level correct?

Go to Step 4

Go to Step 3

3

Add coolant as needed.

Is the repair complete?

System OK

Go to Step 4

4

Inspect the timing belt for tension or damage.

Is the timing belt OK?

Go to Step 6

Go to Step 5

5

Correct any problem with the drive belts.

Is the repair complete?

System OK

Go to Step 6

6

Inspect the coolant hoses for leaks or kinks.

Are the coolant hoses OK?

Go to Step 8

Go to Step 7

7

Repair any problem with the coolant hoses.

Is the repair complete?

System OK

Go to Step 8

8

Inspect the surge tank cap.

Is the surge tank cap OK?

Go to Step 10

Go to Step 9

9

Repair or replace the surge tank cap as needed.

Is the repair complete?

System OK

Go to Step 10

10
  1. Set the A/C switch OFF on vehicles equipped with air conditioning.
  2. Set the blower motor switch on 4.
  3. Set the heater control to full hot.
  4. Turn the ignition ON.
  5. Inspect for airflow from the heater outlet.

Is there heavy airflow from the heater outlet?

Go to Step 11

Go to Step 25

11

Inspect for a change in the airflow at various blower speeds.

Does the blower speed increase as the switch is turned from 1 to 4?

Go to Step 12

Go to Blower Motor Malfunction

12
  1. Set the A/C switch to OFF, on vehicles equipped with air conditioning.
  2. Set the temperature lever to full hot.
  3. With the engine sufficiently cool, remove the surge tank cap.
  4. Start the vehicle and idle the engine.
  5. Watch for the flow of the coolant.

Is the coolant flow visible?

Go to Step 14

Go to Step 13

13
  1. Inspect for the following conditions:
    2. • Restriction in the cooling system
    • Failed water pump impeller
    • Faulty thermostat
  2. Make repairs to the cooling system, as needed.

Are the repairs complete?

System OK

Go to Step 15

14
  1. Inspect the vehicle for cold air leaks at the following locations:
    2. • Dash
    • Heater cases
    • Vents
  2. Inspect under the seat for obstructions.
  3. Repair any leaks or obstructions.

Are the repairs complete?

System OK

--

15
  1. Turn the ignition OFF.
  2. Turn the temperature control knob to full cold, then rapidly to full hot.
  3. Listen for the sound of the temperature door slam just before reaching the end of the travel range of the control knob.

Did the door slam?

Go to Step 17

Go to Step 16

16
  1. Inspect the temperature door for the following:
    2. • Travel
    • Cables
    • Linkage
  2. Verify the accuracy of the temperature controls at full hot.
  3. Verify the accuracy of the temperature controls at full cold.

Is the repair complete?

System OK

--

17
  1. Set the temperature door to full hot.
  2. Start the vehicle.
  3. Inspect the temperature of the heater inlet hose and the heater outlet hose by feel.

Is the heater inlet hose hot and the heater outlet hose warm?

Go to Step 18

Go to Step 21

18

Inspect the thermostat.

Is the thermostat installed and seated properly?

Go to Step 19

Go to Step 20

19

Replace the thermostat.

Is the repair complete?

System OK

--

20

Install the thermostat.

Is the repair complete?

System OK

--

21

Inspect the heater hoses for proper installation.

Are heater hoses reversed?

Go to Step 22

Go to Step 23

22

Install the heater hoses properly.

Is the repair complete?

System OK

Go to Step 25

23
  1. Back flush the heater core.
  2. Drain the cooling system.
  3. Replace the coolant.
  4. Warm the engine to an average operating temperature.
  5. Feel the heater inlet hose and the heater outlet hose.

Is the heater inlet hose hot and the heater outlet hose warm?

System OK

Go to Step 24

24

Replace the heater core.

Is the repair complete?

System OK

--

25

Inspect the system using the Control Settings/Correct Results tests.

Is the repair complete?

System OK

Go to Step 26

26

Inspect for airflow from the defroster or the vent outlets.

Is there high airflow from the defroster or the vent outlets?

Go to Step 27

Go to Step 28

27

Adjust the heater door at the floor and the vent door to get the proper airflow.

Is the repair complete?

System OK

--

28

Switch the mode knob to defrost.

Is the defroster airflow OK?

Go to Step 29

Go to Step 30

29
  1. Remove the heater outlet and inspect for obstructions.
  2. Remove any obstructions in the heater outlet.

Is the repair complete?

System OK

--

30

Inspect for airflow change at various blower speeds.

Does the blower speed increase as the control is turned from 1 to 4?

Go to Step 31

Go to Blower Motor Malfunction

31

Inspect for obstructions in the system at the blower inlet.

Are there any obstructions?

Go to Step 32

Go to Step 33

32

Remove the obstructions in the system at the blower inlet.

Is the repair complete?

System OK

--

33
  1. Set the blower on 4.
  2. Rotate the temperature control from full hot to full cold.
  3. Listen for an airflow change.

Does the airflow change?

Go to Step 34

Go to Step 35

34
  1. Inspect the temperature door for the following:
    2. • Travel
    • Cables
    • Linkage
    • Control
  2. Verify the accuracy of the temperature controls at full hot.

Is the repair complete?

System OK

--

35
  1. Inspect the system for any obstruction between the blower and the system outlets.
  2. Remove any obstruction.

Is the repair complete?

System OK

--