HVAC Compressor Clutch Does Not Disengage. Buick GL7 (Export) 2000

For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: A/C compressor clutch will not disengage when no A/C request has been made and no Powertrain DTC has been set.
1 | Did you review the Compressor Controls Circuit Description and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms
2 | Verify that the HVAC compressor clutch does not disengage. Does the HVAC compressor clutch operate normally? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3

3

1. Disconnect the Powertrain Control Module (PCM) connector C2.
2. Turn the ignition switch to the RUN position.

Does the A/C compressor clutch coil disengage?

--

Go to Step 4

Go to Step 5

4 | Important: Perform the reprogramming procedure for the PCM. Replace the Powertrain Control Module (PCM). Is the repair complete? | -- | Go to Step 12 | --

5

1. Disconnect the A/C CLU relay from the underhood accessory wiring junction block.
2. Turn the ignition switch to the RUN position.

Does the A/C compressor clutch coil disengage?

--

Go to Step 6

Go to Step 9

6

1. Turn the ignition switch to the OFF position.
2. Connect a DMM between the PCM connector C2 terminal 39 and ground. Refer to Circuit Testing in Wiring Systems.
3. Measure for continuity in circuit 459 to ground. Refer to Circuit Testing in Wiring Systems.

Is circuit 459 continuous to ground?

--

Go to Step 7

Go to Step 8

7 | Repair a short to ground in circuit 459 between the underhood accessory wiring junction block and the PCM connector C2. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 12 | --
8 | Replace the A/C CLU relay. Refer to Compressor Relay Replacement . Is the repair complete? | -- | Go to Step 12 | --

9

1. Disconnect the A/C compressor clutch coil connector. Refer to Air Conditioning Clutch Coil Removal .
2. Connect a DMM between the A/C compressor clutch coil connector terminal B and ground. Refer to Circuit Testing in Wiring Systems.
3. Turn the ignition switch to the RUN position.
4. Measure for voltage on circuit 59.

Is voltage present on circuit 59?

--

Go to Step 10

Go to Step 11

10 | Repair a short to B+ on circuit 59 between the underhood accessory wiring junction block and the A/C compressor clutch coil. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 12 | --
11 | Replace the A/C compressor clutch coil. Refer to Air Conditioning Clutch Coil Replacement . Is the repair complete? | -- | Go to Step 12 | --

12

1. Turn the ignition switch to the OFF position.
2. Reconnect all connectors/components disconnected.
3. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3