GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Express 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 HVAC Compressor Clutch Does Not Engage

Step

Action

Value(s)

Yes

No

1

Was the HVAC Compressor Controls System Check preformed?

--

Go to Step 2

Go to HVAC Compressor Controls System Check

2

Test condition of diode D102, use a J 39200 to perform the test.

Is the diode opened or shorted?

--

Go to Step 39

Go to Step 3

3
  1. Ensure that the following conditions are present:
    2. • All fuses are in good condition
    • The A/C compressor clutch rotates freely
    • The drive belt is in place and in good condition
    • No diagnostic trouble codes are present
    • All grounds are clean and tight
    • The A/C compessor enable relay is properly seated in its socket
  2. Place the vehicle in an area with an ambient air temperature greater than 10°C (50°F).
  3. Start the engine.
  4. Idle the engine at approximately 1000 RPM.
  5. Place the blower motor switch on the heater and A/C controller in the HI position.
  6. Observe that the blower motor operates.
  7. Place the mode switch on the heater and A/C controller in the MAX A/C position.
  8. Place the temperature control dial on the heater and A/C controller in the fully counterclockwise or cold position.
  9. The system should produce cold air.
  10. Observe the A/C compressor clutch for 5 minutes.

Does the A/C compressor clutch energize?

--

Go to CCOT Air Conditioning (A/C) System Diagnosis

Go to Step 4

4
  1. Turn the ignition switch to the OFF position.
  2. Place the heater and A/C controller in the OFF position.
  3. Remove the A/C compressor enable relay from the socket.
  4. Momentarily connect a fused jumper wire between the A/C compressor enable relay socket, cavity D3 and cavity D1.
  5. Place the ignition switch in the RUN position.
  6. Listen for compressor clutch operation sounds.

Does the A/C compressor clutch energize?

--

Go to Step 7

Go to Step 5

5
  1. Remove the fused jumper wire.
  2. Disconnect the A/C compressor clutch connector.
  3. Connect a J 39200 to the A/C compressor clutch connector, cavity A for CKT 150 (BLK), and ground.

Is continuity present?

--

Go to Step 6

Go to Step 22

6

Connect a J 39200 between the A/C compressor clutch connector, cavity B for CKT 59 (DK GRN), and the underhood fuse-relay center, cavity D1.

Is continuity present?

--

Go to Step 23

Go to Step 24

7

Connect an unpowered test lamp to the underhood fuse-relay center, cavity D3, and ground.

Does the test lamp light?

--

Go to Step 8

Go to Step 25

8

Connect an unpowered test lamp to the underhood fuse-relay center, cavity C3, and ground.

Does the test lamp light?

--

Go to Step 9

Go to Step 26

9
  1. Disconnect the vehicle control module (VCM) connector C3, for the gasoline engine vehicle or the powertrain control module (PCM) connector C3, for the diesel engine vehicle.
  2. Connect a J 39200 between the underhood fuse-relay center, cavity C1, and VCM connector C3, cavity 1, or PCM connector C3, cavity D5, for CKT 459 (DK GRN/WHT).

Is continuity present?

--

Go to Step 10

Go to Step 27

10
  1. Install the A/C compressor enable relay in the socket.
  2. Connect a fused jumper wire from VCM connector C3, cavity 1, on a gasoline engine vehicle, or PCM connector C3, cavity D5, on a diesel engine vehicle, for CKT 459 (DK GRN/WHT), to ground.

Does the A/C compressor clutch energize?

--

Go to Step 11

Go to Step 28

11
  1. Disconnect the A/C compressor high pressure cutoff switch connector.
  2. Disconnect the PCM connector C1, for the diesel engine.
  3. Connect a J 39200 between the A/C compressor high pressure cutoff switch connector, cavity A, and VCM connector C3, cavity 25, on a gasoline engine vehicle, or PCM connector C1, cavity C2, on a diesel engine vehicle, for CKT 762 (DK GRN/WHT).

Is continuity present?

--

Go to Step 12

Go to Step 29

12
  1. Reconnect connector C3 for the VCM in gasoline engine vehicles, or connector C1, and connector C3 for the PCM in diesel engine vehicles.
  2. Disconnect the A/C compressor clutch connector.
  3. Connect an unpowered test lamp to the A/C compressor clutch connector, cavity B for CKT 59 (DK GRN), and ground.
  4. Connect a fused jumper wire between B+ and the A/C compressor high pressure cutoff switch connector, cavity A for CKT 762 (DK GRN/WHT).
  5. Ensure that the jumper wire is clear of the fan blades.
  6. Start the engine.
  7. Operate the engine at approximately 1000 RPM.

Does the test lamp light?

--

Go to Step 13

Go to Step 30

13
  1. Turn the ignition switch to the OFF position.
  2. Remove the fused jumper wire.
  3. Connect a ect a J 39200 between pin A and pin B of the A/C compressor high pressure cutoff switch.

Is continuity present?

--

Go to Step 14

Go to Step 31

14

Does the vehicle have a gasoline engine?

--

Go to Step 17

Go to Step 15

15
  1. Disconnect the A/C compressor low pressure cutout switch connector.
  2. Connect a J 39200 between the A/C compressor low pressure cutout switch connector, cavity B, and the A/C compressor high pressure cutoff switch connector, cavity B for CKT 603 (DK GRN).

Is continuity present?

--

Go to Step 16

Go to Step 32

16

Connect a J 39200 between pin A and pin B of the A/C compressor low pressure cutout switch.

Is continuity present?

--

Go to Step 20

Go to Step 33

17
  1. Disconnect the A/C compressor low pressure cutout switch connector.
  2. Connect a J 39200 between the A/C compressor low pressure cutout switch connector, cavity A, and ground.

Is continuity present?

--

Go to Step 18

Go to Step 34

18

Connect a J 39200 between pin A and pin B of the A/C compressor low pressure cutout swich.

Is continuity present?

--

Go to Step 19

Go to Step 33

19
  1. Disconnect the VCM connector C3.
  2. Connect a J 39200 between the VCM connector C3, cavity 30, and the A/C compressor low pressure cutout switch connector, cavity B for CKT 603 (DK GRN).

Is continuity present?

--

Go to Step 20

Go to Step 35

20
  1. Disconnect the heater and A/C controller connector C2.
  2. Connect a J 39200 between heater and A/C controller connector C2, cavity H, and the A/C compressor low pressure cutout switch connector, cavity A , on a diesel engine vehicle, or the A/C compressor high pressure cutoff switch connector, cavity B, on a gasoline engine vehicle, for CKT 66 (LT GRN).

Is continuity present?

--

Go to Step 21

Go to Step 36

21
  1. Place the ignition switch in the RUN position.
  2. Connect an unpowered test lamp to heater and A/C controller connector C2, cavity E for CKT 141 (BRN), and ground.

Does the test lamp light?

--

Go to Step 37

Go to Step 38

22

Repair the open in CKT 150 between the A/C compressor clutch and ground G103.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

23

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

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

24

Repair the open in CKT 59 (DK GRN) between the A/C compressor enable relay connector and the A/C compressor clutch connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

25

Repair the open in CKT 639 (PNK) between the IGN E fuse and the A/C compressor enable relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

26

Repair the open in CKT 1240 (ORN) between the A/C fuse and the A/C compressor enable relay connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

27

Repair the open in CKT 459 (DK GRN/WHT) between the A/C compressor enable relay connector and the VCM connector C3, on a gasoline engine vehicle, or the PCM connector C3, on a diesel engine vehicle.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

28

Replace the A/C compressor enable relay.

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

29

Repair the open in CKT 762 (DK GRN/WHT) between the A/C high pressure cutoff switch connector, and the VCM connector C3, in a gasoline engine vehicle or the PCM connector C1, in a diesel engine vehicle.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

30

Replace the VCM in a gasoline engine vehicle or the PCM in a diesel engine vehicle.

Refer to VCM Replacement/Programming in Engine Controls (4.3L).

Refer to VCM Replacement/Programming in Engine Controls (5.0L, 5.7L).

Refer to Powertrain Control Module Replacement/Programming in Engine Controls (6.5L).

Refer to VCM Replacement/Programming in Engine Controls (7.4L).

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

31

Replace the A/C compressor high pressure cutoff switch.

Refer to Compressor Control Switches Removal.

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

32

Repair the open in CKT 603 (DK GRN) between the A/C compressor low pressure cutout switch connector and the A/C compressor high pressure cutoff switch connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

33

Replace the A/C compressor low pressure cutout switch.

For additional information on the replacement of this switch refer to Relays and Sensors Description .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

34

Repair the open in CKT 150 (BLK) between the A/C compressor low pressure cutout switch connector and ground G103.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

35

Repair the open in CKT 603 (DK GRN) between the VCM connector C3 and the A/C compressor low pressure cutout switch connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

36

Repair the open in CKT 66 (LT GRN) between the heater and A/C controller connector C2 and the A/C compressor low pressure cutout switch connector in a diesel engine vehicle, or the A/C compressor high pressure cutoff switch connector in a gasoline engine vehicle.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

37

Replace the heater and A/C controller.

Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

38

Repair the open in CKT 141 (BRN) between the underhood fuse-relay center HTR-A/C fuse 12 and the heater and A/C controller connector.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--

39

Replace diode D102 in the underhood fuse-relay center.

Refer to Wiring Repairs .

Is the repair complete?

--

Go to HVAC Compressor Controls System Check

--