Schematic Reference: HVAC Schematics

DEFINITION: Air does not flow correctly from the air distribution outlets.

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. Turn ON the ignition, with the engine OFF.
2. Turn OFF the HVAC controls.

Is the blower motor OFF?

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Go to Step 3

Go to Blower Motor Always On

Place the blower motor switch in each speed position.

Does the blower motor operate at all?

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Go to Step 4

Go to Blower Motor Inoperative

Does the blower motor operate in each speed position?

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Go to Step 5

Go to Blower Motor Malfunction

Place the recirculation switch in the recirculation and ambient air positions.

Does the recirculation actuator move from the recirculation position to the ambient air position?

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Go to Step 6

Go to Air Recirculation Malfunction

Place the mode switch in each position.

Is the air flow sufficient from the correct outlets in each mode?

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

Go to Step 7

1. Turn OFF the ignition.
2. Disconnect the mode actuator.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition 3 voltage circuit of the mode actuator with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

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Go to Step 8

Go to Step 16

Measure the voltage from the 5-volt reference circuit of the mode actuator to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 9

Go to Step 12

Test the mode door control circuit of the mode actuator for an open, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 19

Go to Step 10

10

1. Turn OFF the ignition.
2. Connect the mode actuator.
3. Connect the IPM.
4. Turn ON the ignition, with the engine OFF.
5. Measure the voltage from the mode door control circuit of the mode actuator to a good ground.
6. With a scan tool, command the mode actuator to DEFROST and to A/C.

Does the voltage measure near the specified value for each commanded state?

0.1 V DEFROST

4.95 V A/C

Go to Step 13

Go to Step 11

1. With a scan tool, observe the Htr./Def./A/C Dr Actual parameter in the Instrument Panel Module data list.
2. Connect a 3-amp fused jumper wire between the mode door control circuit and the 5-volt reference circuit of the mode actuator. (Drives the actuator toward the vent position.)
3. Record the maximum value of the Htr./Def./A/C Dr Actual parameter.
4. Remove the fused jumper wire. Connect the 3-amp fused jumper wire between the mode door control circuit of the mode actuator and a good ground. (Drives the actuator toward the defrost position.)
5. Record the minimum value of the Htr./Def./A/C Dr Actual parameter.
6. Subtract the minimum recorded value from the maximum recorded value.

Does the result of your calculation indicate that the door travel range is greater than the specified value?

200 Counts

Go to Step 14

Go to Step 13

Test the 5-volt reference circuit of the mode actuator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 19

Go to Step 15

Inspect the mode door and the mode actuator for the following conditions:

Did you find and correct the condition?

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Go to Step 19

Go to Step 14

Inspect for poor connections at the harness connector of the mode 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 19

Go to Step 17

Inspect for poor connections at the harness connector of the IPM. 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 19

Go to Step 18

Repair the ignition 3 voltage circuit of the mode actuator. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 19

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Important: Perform the recalibration procedure for the mode actuator.

Replace the mode actuator. Refer to Mode Actuator Replacement .

Did you complete the replacement?

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Go to Step 19

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Important: Perform the recalibration procedure for the IPM.

Replace the IPM. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

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Go to Step 19

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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 2