For 1990-2009 cars

## HVAC Compressor Clutch Does Not Engage L61

### 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 120°C (248°F). The engine coolant indicator will illuminate at this temperature.

1. The HVAC control assembly is inoperative when the HVAC control unit does not respond to any operator control request to enable the A/C compressor. The blower motor may still operate independent of the A/C controls.

Step | Action | Values | 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: The 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 button so it's in the ON position.
4. Place the air temperature switch 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. Ensure that the ignition key is in the OFF position.
4. Install the J 43600 ACR 2000.
5. Record the ambient air temperature at the vehicle.
6. Record readings of the low and high side STATIC pressures.
7. Compare the pressure values with the specifications for the ambient air temperature. Refer to Air Conditioning (A/C) System Performance Test .

Are the pressure values within the specifications for the ambient air temperature, and within 103 kPa (15 psi) of each other?

--

Go to Step 5

Go to Leak Testing

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 103 kPa (15 psi) of each other?

--

Go to Step 6

Go to Step 19

6 | Is the HVAC control assembly inoperative? | -- | Go to Step 10 | Go to Step 7
7 |

1. Start the engine.
2. With a scan tool, observe the A/C request parameter in the Powertrain Control Module General Info Inputs/ Outputs Data list.
3. Place the blower motor switch in the maximum speed position.
4. Place the mode switch in the VENT position.
5. Place the A/C request switch in the ON position.

Does the scan tool indicate that the A/C request signal is YES?

--

Go to Step 8

Go to Step 12

8 | With a scan tool, observe the A/C Relay Commanded parameter in the Powertrain Control Module Scan Tool Data list. Does the scan tool indicate that the A/C Commanded 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 15
10 | Test the voltage supply circuits to the HVAC control assembly 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 35 | Go to Step 11
11 | Test the ground circuit to the HVAC control assembly for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 35 | Go to Step 26
12 |

1. Start the engine.
2. Place the A/C request switch in the ON position.
3. Measure the voltage on the request circuit at the Body Control Module (BCM) to a good ground.

Does the voltage measure near the specified value?

12 V

Go to Step 27

Go to Step 17

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 18

15 |

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 16

Go to Step 21

16 |

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 23

17 | Test the request signal circuit for a high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 35 | Go to Step 26
18 | 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 35 | Go to Step 20
19 | 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 35 | Go to Step 24
20 | 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 35 | Go to Step 26
21 | 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 35 | --
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 35 | --
23 | Test the control circuit of the A/C compressor clutch relay for an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 35 | Go to Step 28
24 | Inspect for poor connections at the harness connector of the A/C High 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 35 | 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 35 | Go to Step 30
26 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 35 | Go to Step 32
27 | Inspect for poor connections at the BCM. 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 35 | Go to Step 33
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 35 | Go to Step 34
29 | Replace the A/C high pressure switch. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 35 | --
30 | Replace the A/C compressor clutch relay. Did you complete the replacement? | -- | Go to Step 35 | --
31 | Replace the A/C compressor clutch assembly. Refer to Compressor Clutch Assembly Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | -- | Go to Step 35 | --
32 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 35 | --
33 | Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | -- | Go to Step 35 | --
34 | Important: Perform the reprogramming procedure for the PCM. Replace the Powertrain Control Module (PCM). Refer to one of the following procedures Refer to Powertrain Control Module Replacement in Engine Controls-2.2L. Did you complete the replacement? | -- | Go to Step 35 | --
35 | 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

### 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 (237°F). The engine coolant indicator will illuminate at this temperature.

1. The HVAC control assembly is inoperative when the HVAC control unit does not respond to any operator control request to enable the A/C compressor. The blower motor may still operate independent of the A/C controls.

Step | Action | Values | 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 Module 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: The 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 button so it's in the ON position.
4. Place the air temperature switch 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. Ensure that the ignition key is in the OFF position.
4. Install the J 43600 ACR 2000.
5. Record the ambient air temperature at the vehicle.
6. Record readings of the low and high side STATIC pressures.
7. Compare the pressure values with the specifications for the ambient air temperature. Refer to Air Conditioning (A/C) System Performance Test .

Are the pressure values within the specifications for the ambient air temperature, and within 103 kPa (15 psi) of each other?

--

Go to Step 5

Go to Leak Testing

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 103 kPa (15 psi) of each other?

--

Go to Step 6

Go to Step 19

6 | Is the HVAC control assembly inoperative? | -- | Go to Step 10 | Go to Step 7
7 |

1. Start the engine.
2. With a scan tool, observe the A/C request parameter in the EngineControl Module General Info Inputs/ Outputs Data list.
3. Place the blower motor switch in the maximum speed position.
4. Place the mode switch in the VENT position.
5. Place the A/C request switch in the ON position.

Does the scan tool indicate that the A/C request signal is YES?

--

Go to Step 8

Go to Step 12

8 | With a scan tool, observe the A/C Relay Commanded parameter in the Engine Control Module Scan Tool Data list. Does the scan tool indicate that the A/C Commanded 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 15
10 | Test the voltage supply circuits to the HVAC control assembly 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 35 | Go to Step 11
11 | Test the ground circuit to the HVAC control assembly for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 35 | Go to Step 26
12 |

1. Start the engine.
2. Place the A/C request switch in the ON position.
3. Measure the voltage on the request circuit at the Body Control Module (BCM) to a good ground.

Does the voltage measure near the specified value?

12 V

Go to Step 27

Go to Step 17

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 18

15 |

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 16

Go to Step 21

16 |

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 23

17 | Test the request signal circuit for a high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 35 | Go to Step 26
18 | 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 35 | Go to Step 20
19 | 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 35 | Go to Step 24
20 | 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 35 | Go to Step 26
21 | 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 35 | --
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 35 | --
23 | Test the control circuit of the A/C compressor clutch relay for an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 35 | Go to Step 28
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 35 | 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 35 | Go to Step 30
26 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 35 | Go to Step 32
27 | Inspect for poor connections at the BCM. 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 35 | Go to Step 33
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 35 | Go to Step 34
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 35 | --
30 | Replace the A/C compressor clutch relay. Did you complete the replacement? | -- | Go to Step 35 | --
31 | Replace the A/C compressor clutch assembly. Refer to Compressor Clutch Assembly Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | -- | Go to Step 35 | --
32 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 35 | --
33 | Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | -- | Go to Step 35 | --
34 | Important: Perform the reprogramming procedure for the ECM. Replace the Engine Control Module (ECM). Refer to Engine Control Module Replacement in Engine Controls-3.0L. Did you complete the replacement? | -- | Go to Step 35 | --
35 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 4