GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Aurora 🢒 Body and Accessories 🢒 Wiring Systems 🢒 HVAC Compressor Clutch Does Not Disengage

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

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 - Automatic

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

Does the A/C compressor clutch engage and disengage with each command?

Go to Step 3

Go to Step 7

3
  1. Start the engine.
  2. Place the A/C request switch in the OFF position.
  3. With a scan tool, observe the Commanded A/C parameter in the PCM Engine Data list.

Does the scan tool display OFF?

Go to Step 12

Go to Step 4

4

With a scan tool, observe the Control Head (Desired) parameter in the DIM A/C Information list.

Does the scan tool display A/C OFF?

Go to Step 5

Go to Step 6

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 12

Go to Step 11

6

With a scan tool, observe the A/C Requested parameter in the IPM HVAC System Data list.

Does the scan tool display NO?

Go to Step 11

Go to Step 10

7
  1. Turn OFF the ignition.
  2. Disconnect the A/C compressor clutch relay.
  3. Turn ON the ignition, with the engine OFF.

Does the A/C compressor clutch disengage?

Go to Step 13

Go to Step 8

8

Disconnect the A/C compressor.

Does the A/C compressor clutch disengage?

Go to Step 9

Go to Step 14

9

Repair the short to voltage in the A/C compressor clutch supply voltage circuit of the A/C relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 18

--

10

Inspect for poor connections at the harness connector of the instrument panel 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 18

Go to Step 15

11

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.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

12

Inspect for poor connections at the harness connector of the powertrain 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 18

Go to Step 17

13

Replace the A/C compressor clutch relay.

Did you complete the replacement?

Go to Step 18

--

14

Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement .

Did you complete the replacement?

Go to Step 18

--

15

Replace the instrument panel module. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 18

--

16

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

Did you complete the replacement?

Go to Step 18

--

17

Replace the powertrain control module. Refer to one of the following procedures:

    •  Powertrain Control Module Replacement in Engine Controls-3.5L
    •  Powertrain Control Module Replacement in Engine Controls-4.0L

Did you complete the replacement?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2