For 1990-2009 cars

Step | Action | Values | Yes | No
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Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The A/C compressor clutch will not disengage when an A/C request has not been made and a Powertrain DTC has not been set.
1 | Did you review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Manual
2 |

1. Start the engine.
2. Place the blower motor switch in the OFF position.
3. Place the A/C request switch in the OFF position.

Does the A/C compressor operate?

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Go to Step 3

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

3 | With a scan tool, observe the A/C request parameter in the Powertrain data list 2. Does the scan tool indicate that the A/C request parameter is OFF? | -- | Go to Step 4 | Go to Step 6
4 | With a scan tool, observe the A/C Commanded parameter in the Powertrain data list 2. Does the scan tool indicate that the A/C Commanded parameter is OFF? | -- | Go to Step 5 | Go to Step 14
5 | Test the control circuit of the A/C compressor clutch relay for an short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 7
6 |

1. Start the engine.
2. Place the A/C switch in the OFF position.
3. Measure the voltage on the request circuit at the Body Control Module (BCM) to a good ground.

Does the voltage measure near the specified value?

12 V

Go to Step 9

Go to Step 13

7 | Remove the A/C compressor clutch relay. Does the A/C compressor clutch turn OFF? | -- | Go to Step 10 | Go to Step 8
8 | Test the A/C compressor clutch voltage supply circuit, at the A/C compressor clutch 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 20 | Go to Step 11
9 | Test the A/C switch request signal circuit 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 20 | Go to Step 12
10 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 15
11 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 16
12 | Inspect for poor connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 17
13 | Inspect for poor connections at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 18
14 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19
15 | Replace the A/C compressor clutch relay. Did you complete the replacement? | -- | Go to Step 20 | --
16 | Replace the A/C compressor clutch. Refer to Compressor Clutch Plate and Hub Assembly Removal and Compressor Clutch Plate/Hub Assembly Install in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | -- | Go to Step 20 | --
17 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 20 | --
18 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 20 | --
19 | Important: Perform the programming procedure for the PCM. Replace the PCM. Refer to one of the following procedures:

• | Powertrain Control Module Replacement in Engine Controls-2.2L

• | Powertrain Control Module Replacement in Engine Controls-3.4L

Did you complete the replacement?

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Go to Step 20

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20 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2