Schematic Reference: HVAC Schematics

DEFINITION: The temperature can not 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

2

1. Disconnect the scan tool.
2. Turn OFF the ignition.
3. Calibrate the actuators. Refer to Actuator Recalibration .
4. Install a scan tool.
5. Turn ON the ignition, with the engine OFF.
6. Observe the current DTC list in Heating and Air Conditioning using the scan tool.

Does DTC B1340 or DTC B1341 set?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

Place the blower motor switch in each speed position.

Does the blower motor operate correctly for each speed position?

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Go to Step 4

Go to Blower Motor Inoperative

Does the blower motor provide sufficient airflow?

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Go to Step 5

Go to Blower Motor Malfunction

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

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

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Go to Step 6

Go to Air Recirculation Malfunction

With the heater or with the defroster ON, does the customer concern occur?

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Go to Step 7

Go to Step 8

1. Place the blower motor switch in the OFF position.
2. Turn OFF the HVAC controls.

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 8

1. Turn OFF the ignition.
2. Turn ON the ignition, with engine OFF.
3. With a scan tool, command the right and left air temperature actuators Hot and Cold.
4. Observe the Act. Pas Mix Door Pos. parameter and the Act. Dr. Mix Door Pos. parameter.

Do the counts change when actuators are commanded?

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Go to Step 9

Go to Step 16

9

Inspect the cooling system for the following conditions:

Did you find and correct the condition?

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Go to Step 27

Go to Step 10

Check the inside air temperature sensor for proper installation. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

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Go to Step 27

Go to Step 11

Inspect for airflow through the inside air temperature sensor by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

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Go to Step 12

Go to Step 18

1. Install a thermometer near the inside air temperature sensor.
2. With a scan tool, observe the In Car Temperature parameters in the Heating and A/C data list.

Does the scan tool indicate sensor temperatures near the thermometer temperatures within the specified range?

-3 to +3°C

(-5 to +5°F)

Go to Step 13

Go to Step 15

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

Is the Solar Sensor parameter greater than the specified value?

230 Counts

Go to Step 14

Go to Step 21

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

Do the counts change?

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

Go to Step 21

Test the resistance at the inside air temperature sensor. Refer to Sensor Resistance Table .

Is the resistance measurement near the value in the Sensor Resistance Table?

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Go to Step 22

Go to Step 20

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

Did you find and correct the condition?

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Go to Step 27

Go to Step 17

Test the ignition 3 voltage circuit on the suspected actuator for a short to ground, an open, or a 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 27

Go to Step 19

Inspect the aspirator tube and the HVAC module for the following conditions:

Did you find and correct the condition?

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Go to Step 27

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Inspect for poor connections at the harness connector of the suspected 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 27

Go to Step 25

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 27

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 27

Go to Step 24

Inspect for poor connections at the harness connector of the 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?

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Go to Step 27

Go to Step 26

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 27

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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 27

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Important: Perform the recalibration procedure for the air temperature actuator.

Replace the suspected 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 27

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Important: Perform the recalibration procedure for the HVAC control processor.

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

Did you complete the replacement?

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Go to Step 27

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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