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Makes 🢒 Buick 🢒 1999 🢒 Park Avenue 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 HVAC Compressor Clutch Does Not Engage

HVAC Compressor Clutch Does Not Engage for Buick Park Avenue 1999

Step

Action

Value(s)

Yes

No

DEFINITION: The A/C compressor does not engage when requested by the operator.

1
  1. Connect the Scan Tool .
  2. Start the engine.

Are any compressor disabling diagnostic trouble codes set by the Body Control Module (SBM) or the Powertrain Control Module (PCM)?

--

Go to the appropriate Diagnostic Trouble Code (DTC) Table

Go to Step 2

2

Using the Scan Tool view SBM data.

Is the A/C Clutch (Actual) ON?

--

Go to Step 9

Go to Step 3

3

Using the Scan Tool view A/C pressure status. Is the A/C pressure status NORMAL?

NORMAL

Go to Step 4

Go to Step 6

4

Using the Scan Tool view the Battery voltage.

Is the battery voltage greater then the specified value?

10.5 V

Go to Step 5

Go to Charging System Check

5

Using the Scan Tool view the A/C temperature status.

Is the A/C temperature status OK?

--

Go to Step 6

Go to Cooling Insufficient - Air Conditioning (A/C) Inoperative

6

Using the Scan Tool view the system pressure.

Is the system pressure low?

--

Go to Cooling Insufficient - Air Conditioning (A/C) Inoperative

Go to Step 7

7

Inspect the A/C CLU fuse for an open.

Is the A/C CLU fuse open?

--

Go to Step 8

Go to Step 10

8

Replace the A/C CLU fuse.

Is the A/C CLU fuse replaced?

--

Go to Step 19

--

9
  1. Using the control assembly request A/C operation.
  2. Measure the voltage at the compressor clutch between terminals A and B.

Refer to Measuring Voltage in Wiring Systems.

Is the voltage measured greater then the specified value?

10.5 V

Go to Step 15

Go to Step 7

10

Measure the voltage between terminal A of the compress clutch and ground.

Refer to Measuring Voltage in Wiring Systems.

Is the voltage measured greater then the specified value?

10.5 V

Go to Step 16

Go to Step 11

11
  1. Remove the A/C CLU relay.
  2. Measure voltage at A/C CLU relay terminal 30.

Refer to Measuring Voltage in Wiring Systems.

Is the voltage measured greater then the specified value?

10.5 V

Go to Step 17

Go to Step 12

12

Measure voltage to the A/C CLU relay terminal 86.

Refer to Measuring Voltage in Wiring Systems.

Is the voltage measured greater then the specified value?

10.5 V

Go to Step 13

Go to Step 19

13

Measure voltage at terminal 27 CKT 459 (DK GRN/WHT) at the PCM.

Is the voltage measured greater then the specified value?

10.5 V

Go to Step 18

Go to Step 14

14

Inspect CKT 459 (DK GRN/WHT) for an open or short to battery voltage.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

--

15

Replace the compressor. Refer to Air Conditioning Compressor Replacement

Is the repair complete?

--

Go to Step 20

--

16

Inspect CKT 50 (BLK) for an open condition.

Is the repair complete?

--

Go to Step 20

--

17

Replace the A/C CLU relay.

Has the A/C CLU relay been replaced?

--

Go to Step 20

--

18

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the repair complete?

--

Go to Step 20

--

19
  1. Inspect terminal 86 for proper terminal contact. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
  2. Repair an open condition.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

--

20

Confirm proper operation of the A/C compressor.

Is the A/C compressor operating correctly?

--

System OK

--