For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you review the HVAC Compressor/Condenser Fan Circuit Description and perform the necessary inspections? | Go to Step 2 | Go to Diagnostic Starting Point - HVAC Systems - Manual
2 |

1. Start the engine.
2. Turn the blower switch to the OFF position.
3. Turn the A/C switch to the OFF position.

Does the compressor clutch disengage?

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

Go to Step 3

3 | Disconnect the A/C compressor clutch relay. Does the compressor clutch disengage? | Go to Step 7 | Go to Step 4
4 | Test for a short to voltage in the WHT/RED wire between the A/C compressor clutch relay and the A/C compressor clutch. Does a short to voltage exist? | Go to Step 5 | Go to Step 6
5 | Repair the short to voltage in the WHT/RED wire between the A/C compressor clutch relay and the A/C compressor clutch. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 16 | --
6 | Replace the A/C compressor clutch. Refer to Compressor Clutch Coil Replacement . Is the repair complete? | Go to Step 16 | --
7 |

1. Reconnect the A/C compressor clutch relay.
2. Turn the ignition switch to LOCK.
3. Disconnect the A/C compressor control module connector.
4. Turn the ignition switch to ON.

Does the A/C compressor clutch engage?

Go to Step 8

Go to Step 11

8 | Test for a short to ground in the PNK wire between the A/C compressor clutch relay and the A/C compressor control module. Does a short to ground exist? | Go to Step 9 | Go to Step 10
9 | Repair the short to ground in the PNK wire between the A/C compressor clutch relay and the A/C compressor control module. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 16 | --
10 | Replace the A/C compressor clutch relay. Refer to Compressor Relay Replacement . Is the repair complete? | Go to Step 16 | --
11 |

1. Set the A/C switch to OFF.
2. Set the mode to VENT (this opens the defrost switch).
3. Test for a short to ground in the GRN/BLK wire between the A/C compressor control module connector cavity 10 and the A/C switch connector cavity 3.
4. Test for a short to ground in the GRN/BLK wire between the A/C compressor control module connector cavity 10 and the defrost switch.

Is a short to ground present?

Go to Step 12

Go to Step 13

12 | Repair the short. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | Go to Step 16 | --
13 |

1. Set the A/C switch to OFF.
2. Set the mode to VENT (this opens the defrost switch).
3. Test the A/C switch for continuity between terminals 2 and 3.
4. Test the defrost switch for continuity between terminals 1 and 2.

Is continuity present (switch shorted) in either switch?

Go to Step 14

Go to Step 15

14 | Replace the A/C switch or the defrost switch. Refer to Control Assembly Replacement . Is the repair complete? | Go to Step 16 | --
15 | Replace the A/C compressor control module. Refer to Air Conditioning (A/C) Compressor Control Module Replacement . Is the repair complete? | Go to Step 16 | --
16 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3