GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 SSR 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Too Hot in Vehicle

Diagnostic Aids
    • If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Test for cooling fan operation, if the cooling fans are inoperative the A/C clutch may be disabled due to a high pressure condition.

Test Description

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

  1. To observe the recirculation actuator, lower the glove box off of the upper attachments.

    2.

  2. To ensure actuator movement without removing upper instrument panel (I/P) trim, place hand through glove compartment on top of HVAC case on actuator. Then rotate the air temperature switch while finger is on top of air temperature actuator driveshaft to feel movement.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the cooling is insufficient during A/C operation.

1

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

2
  1. Recalibrate actuators. Refer to Actuator Recalibration .
  2. Turn ON the ignition, with the engine OFF.
  3. Perform Diagnostic Trouble Code (DTC) Displaying .
  4. Observe the Diagnostic Trouble Code (DTC) List .

Does the HVAC control module flash DTC 100?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3
  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch in each speed position.

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

Go to Step 4

Go to Blower Motor Inoperative

4

Does the blower motor operate at the desired speed?

Go to Step 5

Go to Blower Motor Malfunction

5

  1. Place the mode switch in the Vent position.
  2. Place the recirculation switch in the ON position.
  3. Observe the recirculation door.
  4. Place the recirculation switch in the OFF position.

Does the recirculation door move from the recirculation position to the outside air position?

Go to Step 6

Go to Air Recirculation Malfunction

6

Does the customer concern occur when the A/C is OFF?

Go to Step 9

Go to Step 7

7

Important:: The evaporator core temperature must be above 0°C (32°F).

  1. Start the engine.
  2. Place the blower motor switch in the maximum speed position.
  3. Place the A/C request switch in the ON position.
  4. Place the air temperature switch in the coldest position.

Does the A/C compressor operate?

Go to Step 8

Go to HVAC Compressor Clutch Does Not Engage

8

Perform the A/C System Performance Test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

Go to Step 12

Go to Step 9

9

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

Does the air temperature actuator rotate?

Go to Diagnostic Aids

Go to Step 10

10

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 12

Go to Step 11

11

Important: Perform the recalibration procedure for the HVAC control module. Refer to Actuator Recalibration .

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

Did you complete the replacement?

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2