GM Service Manual Online
For 1990-2009 cars only

step

Action

Value(s)

Yes

No

DEFINITION: A/C compressor clutch will not disengage when no A/C request has been made and no disabling DTC has been set.

1

  1. Connect the scan tool to the data link connector (DLC).
  2. Start the engine.
  3. Turn the A/C OFF.

Is the compressor clutch being requested ON by the Powertrain Control Module (PCM)?

--

Go to Step 4

Go to Step 2

2

Is the compressor clutch being requested ON by the Instrument Panel Module (IPM).

--

Go to Step 10

Go to Step 3

3

Is the compressor clutch being requested ON by the Dash Integration Module (DIM).

--

Go to Step 11

Go to Step 5

4

Replace the powertrain control module. Refer to Powertrain Control Module Replacement in Engine Controls.

Is the repair complete?

--

System OK

--

5

Disconnect the A/C CLU relay from the underhood junction block.

Does the A/C clutch disengage?

--

Go to Step 7

Go to Step 6

6

Locate and repair a short to battery in CKT 59. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

System OK

--

7

Measure resistance between A/C CLU relay terminal 85 and ground.

Refer to Testing for Continuity in Wiring Systems.

Is the resistance at the specified range?

0 ohms

Go to Step 8

Go to Step 9

8

Replace the A/C CLU relay.

Is the repair complete?

--

System OK

--

9

Locate and repair a short to ground on CKT 459 between the underhood junction block and the A/C compressor clutch.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

System OK

--

10

Replace the IPM.

Refer to Control Assembly Replacement in Body Control System.

Is the repair complete?

--

System OK

--

11

Replace the DIM.

Refer to Body Control Module Replacement in Body Control System.

Is the repair complete?

--

System OK

--