HVAC Compressor Clutch Does Not Engage. GMC Truck Savana 2000

GM Service Manual Online

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Body and Accessories 🢒 Wiring Systems 🢒 HVAC Compressor Clutch Does Not Engage

Step

Action

Value(s)

Yes

Did you review the HVAC compressor controls circuit description and perform the necessary inspections?

Go to Step 2

Go to Symptoms

Ensure that the following conditions are present:

•	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 compressor enable relay is properly seated in its socket.

Place the vehicle in an area with an ambient air temperature greater than 10°C (50°F).
Start the engine.
Idle the engine at approximately 1000 RPM.
Place the blower motor switch on the heater and A/C controller in the HI position.
Observe that the blower motor operates.
Place the mode switch on the heater and A/C controller in the MAX A/C position.
Place the temperature control dial on the heater and A/C controller in the fully counterclockwise or cold position.
The system should produce cold air.
Observe the A/C compressor clutch for 5 minutes.

Does the A/C compressor clutch energize?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

Using a J 39200 Digital Multimeter (DMM), check diode D102 for continuity in both direction. Refer to Circuit Testing in Wiring Systems.

Is the diode opened or shorted?

Go to Step 39

Go to Step 4

Turn the ignition switch to the OFF position.
Place the heater and A/C controller in the OFF position.
Remove the A/C compressor enable relay from the socket.
Momentarily connect a J 36169-A fused jumper wire between the A/C compressor enable relay socket cavity D3 for CKT 639 (PNK) and cavity D1 for CKT 59 (DK GRN). Refer to Circuit Testing in Wiring Systems.
Place the ignition switch in the RUN position.
Listen for compressor clutch operation sounds.

Does the A/C compressor clutch energize?

Go to Step 7

Go to Step 5

Remove the fused jumper wire.
Disconnect the A/C compressor clutch connector.
Connect a J 39200 DMM to the A/C compressor clutch connector, cavity A for CKT 150 (BLK), and ground. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 6

Go to Step 22

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

Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 23

Go to Step 24

Connect a J 35616-200 unpowered test lamp between underhood fuse-relay center cavity D3 for CKT 639 (PNK) and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp light?

Go to Step 8

Go to Step 25

Connect a J 35616-200 unpowered test lamp between underhood fuse-relay center cavity C3 for CKT 1240 (ORN) and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp light?

Go to Step 9

Go to Step 26

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

Is continuity present?

Go to Step 10

Go to Step 27

Install the A/C compressor enable relay in the socket.
Connect a fused jumper wire between 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) and ground. Refer to Circuit Testing in Wiring Systems.

Does the A/C compressor clutch energize?

Go to Step 11

Go to Step 28

Disconnect the A/C compressor high pressure cutoff switch.
Disconnect PCM connector C1 for the diesel engine.
Connect a J 39200 DMM between 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). Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 12

Go to Step 29

Reconnect VCM connector C3 in gasoline engine vehicles, or PCM connector C1 and PCM connector C3 in diesel engine vehicles.
Disconnect the A/C compressor clutch connector.
Connect an unpowered test lamp between A/C compressor clutch connector cavity B for CKT 59 (DK GRN) and ground. Refer to Circuit Testing in Wiring Systems.
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).
Ensure that the jumper wire is clear of the fan blades.
Start the engine.
Operate the engine at approximately 1000 RPM.

Does the test lamp light?

Go to Step 13

Go to Step 30

Turn the ignition switch to the OFF position.
Remove the fused jumper wire.
Connect a J 39200 DMM between pin A and pin B of the A/C compressor high pressure cutoff switch. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 14

Go to Step 31

Does the vehicle have a gasoline engine?

Go to Step 17

Go to Step 15

Disconnect the A/C compressor low pressure cutout switch connector.
Connect a J 39200 DMM between A/C compressor low pressure cutout switch connector cavity B and A/C compressor high pressure cutoff switch connector cavity B for CKT 603 (DK GRN). Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 16

Go to Step 32

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

Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 20

Go to Step 33

Disconnect the A/C compressor low pressure cutout switch connector.
Connect a J 39200 DMM between A/C compressor low pressure cutout switch connector cavity A for CKT 150 (BLK) and ground. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 18

Go to Step 34

Connect a J 39200 DMM between pin A and pin B of the A/C compressor low pressure cutout switch. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 19

Go to Step 33

Disconnect VCM connector C3.
Connect a J 39200 DMM between VCM connector C3 cavity 30 and A/C compressor low pressure cutout switch connector cavity B for CKT 603 (DK GRN). Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 20

Go to Step 35

Disconnect heater and A/C controller connector C2.
Connect a J 39200 DMM between heater and A/C controller connector C2 cavity H and A/C compressor low pressure cutout switch connector cavity A on a diesel engine vehicle, or A/C compressor high pressure cutoff switch connector cavity B on a gasoline engine vehicle, for CKT 66 (LT GRN). Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 21

Go to Step 36

Place the ignition switch in the RUN position.
Connect a J 35616-200 unpowered test lamp between heater and A/C controller connector C2 cavity E for CKT 141 (BRN), and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp light?

Go to Step 37

Go to Step 38

Repair the open in CKT 150 between the A/C compressor clutch and ground G103. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 40

Replace the A/C compressor.

Refer to Air Conditioning Compressor Replacement for the (4.3L, 5.0L, 5.7L) Engines.

Is the repair complete?

Go to Step 40

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 in Wiring Systems.

Is the repair complete?

Go to Step 40

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

Is the repair complete?

Go to Step 40

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

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 40

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

Is the repair complete?

Go to Step 40

Replace the A/C compressor enable relay.

Is the repair complete?

Go to Step 40

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

Is the repair complete?

Go to Step 40

Replace the VCM in a gasoline engine vehicle or the PCM in a diesel engine vehicle. Refer to the appropriate procedure:

•	VCM Replacement/Programming in Engine Controls (4.3L)

•	VCM Replacement/Programming in Engine Controls (5.0L, 5.7L)

•	Powertrain Control Module Replacement/Programming in Engine Controls (6.5L)

•	VCM Replacement/Programming in Engine Controls (7.4L)

Is the repair complete?

Go to Step 40

Replace the A/C compressor high pressure cutoff switch. Refer to Air Conditioning (A/C) High Pressure Cut-Out Switch Replacement .

Is the repair complete?

Go to Step 40

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 in Wiring Systems.

Is the repair complete?

Go to Step 40

Replace the A/C compressor low pressure cutout switch.

Refer to Pressure Cycling Switch Replacement .

Is the repair complete?

Go to Step 40

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

Is the repair complete?

Go to Step 40

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 in Wiring Systems.

Is the repair complete?

Go to Step 40

Repair the open in CKT 66 (LT GRN) between 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 in Wiring Systems.

Is the repair complete?

Go to Step 40

Replace the heater and A/C controller. Refer to Control Assembly Replacement .

Is the repair complete?

Go to Step 40

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 in Wiring Systems.

Is the repair complete?

Go to Step 40

Replace diode D102 in the underhood fuse-relay center.

Is the repair complete?

Go to Step 40

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3