Schematic Reference: HVAC Schematics

DEFINITION: Air recirculation is inoperative or is always ON.

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. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Air Circulation Valve in the Heating and Air Conditioning data list.
4. Place the recirculation switch in the ON and OFF position.

Does the scan tool indicate the Air Circulation Valve changes state?

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Go to Step 3

Go to Step 11

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the mode switch in the bi-level position.
4. Place the A/C switch in the OFF position.
5. Place the recirculation switch in the ON and OFF position.

Does the recirculation vacuum solenoid valve turn ON and OFF?

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

Go to Step 4

4

1. Turn OFF the ignition.
2. Disconnect the vacuum supply hose.
3. Disconnect the recirculation vacuum solenoid valve.
4. Turn ON the ignition, with the engine OFF.
5. Probe circuit 938 of the recirculation vacuum solenoid valve with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

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Go to Step 5

Go to Step 12

5

1. Connect a test lamp between circuit 921 of the recirculation vacuum solenoid valve and circuit 938 of the recirculation vacuum solenoid valve.
2. With a scan tool, command the Air Circulation Valve ON and OFF.

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

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Go to Step 9

Go to Step 6

6

Does the test lamp remain illuminated with each command?

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Go to Step 8

Go to Step 7

Test circuit 921 of the recirculation vacuum solenoid valve 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 15

Go to Step 11

Test circuit 921 of the recirculation vacuum solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 15

Go to Step 11

Measure the resistance of the recirculation vacuum solenoid valve.

Does the resistance measure near the specified range?

35-40 ohms

Go to Vacuum Control System Diagnostic

Go to Step 15

Inspect for poor connections at the recirculation vacuum solenoid valve. 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 15

Go to Step 13

Inspect for poor connections at the harness connector of the heater and A/C control. 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 15

Go to Step 14

Test circuit 938/925 of the recirculation vacuum solenoid valve for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 15

Go to Step 11

Replace the recirculation vacuum solenoid valve. Refer to Vacuum Electrical Solenoid Replacement - Recirculation Actuator Control .

Did you complete the replacement?

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Go to Step 15

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Important: Perform the recalibration procedure for the heater and A/C control.

Replace the heater and A/C control. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

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Go to Step 15

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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