For 1990-2009 cars

## HVAC Compressor Clutch Does Not Engage L61

### Diagnostic Aids

The Delphi variable displacement type A/C compressor carries a thermal link fuse. The purpose of the thermal link fuse is to open and disable the compressor under extreme load and temperatures above 214°C (417°F). The internal thermal link fuse is serviceable.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The A/C compressor relay output is disabled if engine coolant temperature is above 116°C (120°F). The engine coolant indicator will illuminate at this temperature.

1. Place the mode switch in any position except OFF, and place the air temperature control in a cold setting. Use the bi-level mode for consistent testing of the A/C system operation.

2. The HVAC control module is inoperative when the module does not respond to any operator control requests to enable the A/C compressor. The blower motor may still operate independent of the A/C controls.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set.
1 | Did you review the HVAC operation and perform the necessary inspections? | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Manual
2 |

1. Start the engine.
2. Observe the coolant temperature indicator.

Is the engine coolant temperature indicator illuminated?

Go to Engine Overheating in Engine Cooling

Go to Step 3

3 | Important: For A/C compressor operation, ambient air temperature must be above 4°C (40°F).

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Press the drivers side temperature control switch.
4. Place the drivers side temperature control in the coldest position.

Does the A/C compressor operate?

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

Go to Step 4

4 |

1. Park the vehicle inside or in the shade.
2. Open the windows in order to ventilate the interior of the vehicle.
3. If the A/C system was operating, then allow the A/C system to equalize for approximately 2 minutes.
4. Turn OFF the ignition switch.
5. Install the J 43600 ACR 2000 Air Conditioning Service Center.
6. Record the ambient air temperature at the vehicle.
7. Record readings of the low and high side STATIC pressures.
8. Compare the low and high side pressure values with the allowable limits for the recorded ambient air temperature. Refer to Air Conditioning (A/C) System Performance Test .

Are the low and high side pressure values within the allowable limits for the recorded ambient air temperature, and within 103 kPa (15 psi) of each other?

Go to Step 5

Go to Leak Testing in Heating, Ventilation and Air Conditioning

5 |

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, observe the A/C high side pressure sensor parameter in the powertrain data list.
3. Compare the A/C high side pressure on the scan tool to the high side pressure value on the ACR 2000.

Are the high side pressure values within the 103 kPa (15 psi) of each other?

Go to Step 6

Go to Step 16

6 | Is the HVAC control module inoperative? | Go to Step 15 | Go to Step 7
7 |

1. Start the engine.
2. With a scan tool, observe the A/C Request Signal parameter in the Powertrain data list.
3. Place the air temperature switch in the coldest position.
4. Press the A/C request switch.

Does the scan tool indicate that the A/C Request Signal parameter is YES?

Go to Step 8

Go to Step 27

8 | With a scan tool, observe the A/C Relay Command Parameter in the Powertrain data list. Does the scan tool indicate that the A/C Relay Command parameter is ON? | Go to Step 9 | Go to Step 28
9 | With a scan tool, command the A/C compressor clutch relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? | Go to Step 13 | Go to Step 10
10 |

1. Turn OFF the ignition.
2. Disconnect the A/C compressor clutch relay.
3. Turn ON the ignition, with the engine OFF.
4. Probe the coil side voltage supply circuit of the A/C compressor clutch relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 23

11 |

1. Connect a test lamp between the control circuit of the A/C compressor clutch relay and the coil side voltage supply circuit of the A/C compressor clutch relay.
2. With a scan tool, command the A/C compressor clutch relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 25

Go to Step 12

12 | Does the test lamp remain illuminated with each command? | Go to Step 19 | Go to Step 18
13 |

1. Turn OFF the ignition.
2. Disconnect the A/C compressor clutch relay.
3. Probe the switch side voltage supply circuit of the A/C compressor clutch relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 14

Go to Step 22

14 |

1. Connect a 10 amp fused jumper wire between the switch side voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch.
2. Turn ON the ignition, with the engine OFF.

Does the A/C compressor clutch engage?

Go to Step 25

Go to Step 20

15 | Test the ignition 3 voltage circuit of the HVAC control module for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 17
16 | Test the ground circuit of the A/C refrigerant pressure sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 24
17 | Test the ground circuit of the HVAC control module for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 27
18 | Test the control circuit of the A/C compressor clutch relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 28
19 | Test the control circuit of the A/C compressor clutch relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 28
20 | Test the A/C compressor clutch supply voltage circuit at the A/C compressor clutch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 21
21 | Test the ground circuit of the A/C compressor clutch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 26
22 | Repair the switch side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 34 | --
23 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 34 | --
24 | Inspect for poor connections at the harness connector of the A/C refrigerant pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 29
25 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 30
26 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 31
27 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 32
28 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 33
29 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating,Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 34 | --
30 | Replace the A/C compressor clutch relay. Did you complete the replacement? | Go to Step 34 | --
31 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | Go to Step 34 | --
32 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | Go to Step 34 | --
33 | Important: Perform the reprogramming procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-2.2L. Did you complete the replacement? | Go to Step 34 | --
34 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 4

## HVAC Compressor Clutch Does Not Engage L81

### Diagnostic Aids

The Delphi variable displacement type A/C compressor carries a thermal link fuse. The purpose of the thermal link fuse is to open and disable the compressor under extreme load and temperatures above 214°C (417°F). The internal thermal link fuse is serviceable.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The A/C compressor relay output is disabled if engine coolant temperature is above 116°C (120°F). The engine coolant indicator will illuminate at this temperature.

1. Place the mode switch in any position except OFF, and place the air temperature control in a cold setting. Use the bi-level mode for consistent testing of the A/C system operation.

2. The HVAC control module is inoperative when the module does not respond to any operator control requests to enable the A/C compressor. The blower motor may still operate independent of the A/C controls.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Engine Control DTC has not been set.
1 | Did you review the HVAC operation and perform the necessary inspections? | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Manual
2 |

1. Start the engine.
2. Observe the coolant temperature indicator.

Is the engine coolant temperature indicator illuminated?

Go to Engine Overheating in Engine Cooling

Go to Step 3

3 | Important: For A/C compressor operation, ambient air temperature must be above 4°C (40°F).

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Press the A/C request switch.
4. Place the temperature control in the coldest position.

Does the A/C compressor operate?

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

Go to Step 4

4 |

1. Park the vehicle inside or in the shade.
2. Open the windows in order to ventilate the interior of the vehicle.
3. If the A/C system was operating, then allow the A/C system to equalize for approximately 2 minutes.
4. Turn OFF the ignition switch.
5. Install the J 43600 ACR 2000 Air Conditioning Service Center.
6. Record the ambient air temperature at the vehicle.
7. Record readings of the low and high side STATIC pressures.
8. Compare the low and high side pressure values with the allowable limits for the recorded ambient air temperature. Refer to Air Conditioning (A/C) System Performance Test .

Are the low and high side pressure values within the allowable limits for the recorded ambient air temperature, and within 103 kPa (15 psi) of each other?

Go to Step 5

Go to Leak Testing in Heating, Ventilation and Air Conditioning

5 |

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, observe the A/C refrigerant pressure sensor parameter in the engine control data list.
3. Compare the A/C high side pressure on the scan tool to the high side pressure value on the ACR 2000.

Are the high side pressure values within the 103 kPa (15 psi) of each other?

Go to Step 6

Go to Step 16

6 | Is the HVAC control module inoperative? | Go to Step 15 | Go to Step 7
7 |

1. Start the engine.
2. With a scan tool, observe the A/C Request Signal parameter in the Engine Control data list.
3. Place the air temperature switch in the coldest position.
4. Press the A/C request switch.

Does the scan tool indicate that the A/C Request Signal parameter is YES?

Go to Step 8

Go to Step 27

8 | With a scan tool, observe the A/C Relay Command Parameter in the Engine Control data list. Does the scan tool indicate that the A/C Relay Command parameter is ON? | Go to Step 9 | Go to Step 28
9 | With a scan tool, command the A/C compressor clutch relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? | Go to Step 13 | Go to Step 10
10 |

1. Turn OFF the ignition.
2. Disconnect the A/C compressor clutch relay.
3. Turn ON the ignition, with the engine OFF.
4. Probe the coil side voltage supply circuit of the A/C compressor clutch relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 23

11 |

1. Connect a test lamp between the control circuit of the A/C compressor clutch relay and the coil side voltage supply circuit of the A/C compressor clutch relay.
2. With a scan tool, command the A/C compressor clutch relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 25

Go to Step 12

12 | Does the test lamp remain illuminated with each command? | Go to Step 19 | Go to Step 18
13 |

1. Turn OFF the ignition.
2. Disconnect the A/C compressor clutch relay.
3. Probe the switch side voltage supply circuit of the A/C compressor clutch relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 14

Go to Step 22

14 |

1. Connect a 10 amp fused jumper wire between the switch side voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch.
2. Turn ON the ignition, with the engine OFF.

Does the A/C compressor clutch engage?

Go to Step 25

Go to Step 20

15 | Test the ignition 3 voltage circuit of the HVAC control module for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 17
16 | Test the ground circuit of the A/C refrigerant pressure sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 24
17 | Test the ground circuit of the HVAC control module for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 27
18 | Test the control circuit of the A/C compressor clutch relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 28
19 | Test the control circuit of the A/C compressor clutch relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 28
20 | Test the A/C compressor clutch supply voltage circuit at the A/C compressor clutch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 21
21 | Test the ground circuit of the A/C compressor clutch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 26
22 | Repair the switch side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 34 | --
23 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 34 | --
24 | Inspect for poor connections at the harness connector of the A/C refrigerant pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 29
25 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 30
26 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 31
27 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 32
28 | Inspect for poor connections at the harness connector of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 34 | Go to Step 33
29 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating,Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 34 | --
30 | Replace the A/C compressor clutch relay. Did you complete the replacement? | Go to Step 34 | --
31 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | Go to Step 34 | --
32 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | Go to Step 34 | --
33 | Important: Perform the reprogramming procedure for the ECM. Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls-3.0L. Did you complete the replacement? | Go to Step 34 | --
34 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 4