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?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

1. Disconnect the scan tool.
2. Turn OFF the ignition.
3. Recalibrate the actuators. Refer to Actuator Recalibration .
4. Install a scan tool.
5. Turn ON the ignition, with the engine OFF.
6. Observe the Diagnostic Trouble Code (DTC) List.

Does the scan tool display any DTC B0361, B0363, B0365, B0367, B0441 or B0446?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

Important:: Ambient air temperature must be above 3°C (38°F).

1. Start the engine.
2. Place the HVAC control module in the OFF position.

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 4

Place the blower motor switch in each speed position.

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

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Go to Step 5

Go to Blower Motor Inoperative

Does the blower motor operate in the desired speeds?

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Go to Step 6

Go to Blower Motor Malfunction

1. Place the blower motor switch in the maximum speed position.
2. Place the mode switch in the vent position.
3. Place the recirculation switch in the ON and OFF positions.

Does the recirculation door operate properly?

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Go to Step 7

Go to Air Recirculation Malfunction

7

Inspect the heating and cooling system for the following:

Did you find and correct the condition?

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Go to Step  25

Go to Step 8

1. Turn ON the ignition, with engine OFF.
2. With a scan tool, command the right and left air temperature actuators Hot and Cold.
3. Observe the LH Mix Mtr Position Fee and the RH Mix Mtr Position Fee parameters in Heating and Air Conditioning data list.

Do the counts change when actuators are commanded?

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Go to Step 9

Go to Step 16

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the temperature switches in the warmest positions.
4. Wait 3 minutes to allow the discharge air temperature to stabilize.
5. Install a thermometer near the inside air temperature sensor and record the air temperature.
6. With a scan tool, record the values of the Inside Temp Sensor parameter in the Heating and Air Conditioning data list. Refer to Sensor Resistance Table .

Does the scan tool indicate that the inside air temperature sensor is near the specified value for the recorded air temperature?

-5 to +5°C (-5 to +5°F)

Go to Step  11

Go to Step  10

Inspect for a blocked, malfunctioning, or incorrectly installed inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

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Go to Step  25

Go to Step  14

1. Turn the engine OFF.
2. Install a scan tool.
3. Cover the sunload sensor.
4. Start the engine.
5. Adjust driver side temperature to 22°C (72°F).
6. With a scan tool, observe the Sun Load Sensor data parameter in the Heating, Ventilation and Air Conditioning data list.

Does the scan tool indicate that the Sun Load Sensor parameter is more than the specified value?

230  Counts

Go to Step  12

Go to Step  19

1. Uncover the sunload sensor.
2. Direct a light source at the sunload sensor.

Does the voltage change?

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Go to Step  13

Go to Step  19

Does the customer need to change the set temperature frequently to maintain comfort?

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Go to Symptoms - HVAC Systems - Automatic

System OK

Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  25

Go to Step  15

1. Turn OFF the ignition.
2. Test the inside air temperature sensor resistance. Refer to Sensor Resistance Table .

Does the resistance measure near the specified value?

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Go to Step  20

Go to Step  21

Test the suspect actuator door control circuit for a short to voltage, short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  25

Go to Step  17

Test the suspect actuator ignition 3 voltage circuit for a short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  25

Go to Step  18

Inspect for poor connections at the harness connector of the suspect 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?

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Go to Step  25

Go to Step  23

Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step  25

Go to Step 22

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?

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Go to Step  25

Go to Step  24

Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you complete the replacement?

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Go to Step  25

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Replace the sunload sensor. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

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Go to Step  25

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Replace the suspect air temperature actuator. Refer to Air Temperature Actuator Replacement - Right Side or Air Temperature Actuator Replacement - Left Side .

Did you complete the replacement?

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Go to Step  25

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

Did you complete the replacement?

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Go to Step  25

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Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3