GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

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 perform the HVAC Diagnostic System Check?

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 bi-level switch in the OFF position.

Does the A/C compressor operate?

Go to Step 3

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

3

With the scan tool, observe the A/C commanded parameter in the powertrain control module (PCM) Data List.

Does the scan tool indicate the A/C Relay Command parameter is ON?

Go to Step 4

Go to Step 6

4

With the scan tool, observe the Control Head, desired, parameter in the dash integration module (DIM) A/C Information List.

Does the scan tool display A/C OFF?

Go to Step 5

Go to Step 11

5

With a scan tool, observe the A/C Clutch, desired, parameter in the DIM A/C Information List.

Does the scan tool display OFF?

Go to Step 13

Go to Step 12

6

  1. Turn OFF the ignition.
  2. Disconnect the A/C compressor clutch relay.
  3. Turn the ignition ON.

Does the A/C compressor clutch disengage?

Go to Step 7

Go to Step 8

7

Test the A/C compressor clutch relay control circuit of the A/C compressor clutch 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 19

Go to Step 10

8

Test the A/C compressor clutch supply voltage 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 19

Go to Step 9

9

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 19

Go to Step 15

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 19

Go to Step 14

11

Inspect for poor connections at the harness connector of the HVAC control module. 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 19

Go to Step 16

12

Inspect for poor connections at the dash integration module (DIM). 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 19

Go to Step 17

13

Inspect for poor connections at the harness connector of the 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 19

Go to Step 18

14

Replace the A/C compressor clutch relay.

Did you complete the replacement?

Go to Step 19

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15

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 19

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16

Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

Go to Step 19

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17

Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 19

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18

Important:  Perform the reprogramming procedure for the PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-3.8L.

Did you complete the replacement?

Go to Step 19

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19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2