GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Sunfire 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Too Cold in Vehicle

Test Description

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

  1. This tests for the blower motor functionality.

    2.

  2. This tests for the A/C compressor clutch always on.

    3.

  3. This test is to insure the cooling system is operating normally.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the heating is insufficient.

1

Did you perform the HVAC Diagnostic System Check?

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.
  3. Place the blower switch 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 at the desired speeds?

Go to Step 4

Go to Blower Motor Malfunction

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

Does the recirculation door move to the recirculation position?

Go to Step 5

Go to Air Recirculation Malfunction

5

Place the HVAC control assembly in the OFF position.

Does the A/C compressor operate?

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 6

6

Inspect the cooling system for the following conditions:

    • A low coolant level
    • A loose radiator hose or heater hose
    • A kinked radiator hose or heater hose
    • A missing radiator cap pressure seal
    • A leaking radiator cap

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Perform the Heating Performance Diagnostic. Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Inspect the air temperature door and linkage for the following conditions:

    • High effort to operate air temperature door
    • Broken or binding linkages or air temperature door
    • An obstruction that prevents the air temperature door from operating within it's full range of motion
    • Missing seals to the air temperature door
    • Misaligned seals to the air temperature door

Did you find and correct the condition?

Go to Step 9

Go to High or Low Temperature Control Effort in Heating, Ventilation and Air Conditioning

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2