Schematic Reference: HVAC Schematics

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, command the A/C Orifice Relay ON and OFF.

Does the A/C orifice solenoid turn ON and OFF with each command?

Go to Step 3

Go to Step 5

1. Start the engine.
2. Place the air temperature switch in the coldest position.
3. Place the blower motor switch in the maximum speed position.
4. Operate the A/C system for 5 minutes.
5. With a scan tool, observe the Evaporator Temp Status parameter.
6. With a scan tool, command the A/C Orifice Relay ON and OFF.

Does the Evaporator Temp Status parameter change 1-2°C (2-4°F) with each command?

Go to Step 4

Go to Step 21

1. With a scan tool, observe the A/C Orifice Relay parameter.
2. Increase the engine RPMs.

Does the scan tool indicate that the A/C orifice relay parameter displays Inactive above 3500 RPM?

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

Go to Step 19

1. Turn OFF the ignition.
2. Disconnect the A/C orifice relay.
3. Turn ON the ignition, with the engine OFF.
4. Probe the switch side supply voltage circuit of the A/C orifice relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 14

Connect a test lamp between the switch side supply voltage circuit of the A/C orifice relay and the A/C orifice solenoid supply voltage circuit of the A/C orifice relay.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

Probe the coil side supply voltage circuit of the A/C orifice relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 15

1. Turn OFF the ignition.
2. Disconnect the A/C orifice solenoid.
3. Reconnect the A/C orifice relay.
4. Turn ON the ignition, with the engine OFF.
5. Connect a test lamp between the supply voltage circuit and the ground circuit of the A/C orifice solenoid.
6. With a scan tool, command the A/C Orifice Relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 18

Go to Step 11

1. Connect a test lamp between the control circuit and the coil side supply voltage circuit of the A/C orifice relay.
2. With a scan tool, command the A/C Orifice Relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 20

Go to Step 10

Does the test lamp remain illuminated with each command?

Go to Step 13

Go to Step 12

1. Turn OFF the ignition.
2. Probe the ground circuit of the A/C orifice solenoid with a test lamp that is connected to B+.

Does the test lamp illuminate?

Go to Step 16

Go to Step 17

Test the control circuit of the A/C orifice relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 19

Test the control circuit of the A/C orifice relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 19

Test the switch side supply voltage circuit of the A/C orifice relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

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Test the coil side supply voltage circuit of the A/C orifice relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

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Test the supply voltage circuit of the A/C orifice solenoid for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

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Test the ground circuit of the A/C orifice solenoid for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

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Inspect for poor connections at the harness connector of the A/C orifice solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Go to Step 23

Go to Step 21

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

Go to Step 23

Go to Step 22

Replace the A/C orifice relay.

Did you complete the replacement?

Go to Step 23

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Replace the A/C orifice solenoid. Refer to Orifice Solenoid Replacement .

Did you complete the replacement?

Go to Step 23

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Replace the dash integration module. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 23

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3