For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: HVAC Schematics
1 | Did you review the Air Delivery Description and Operation and the Air Temperature Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual
2 |

1. Star the engine.
2. Turn the A/C switch to the OFF position.
3. Turn the blower switch to any position except OFF.

Does the A/C compressor clutch disengage?

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

Go to Step 3

3 | Remove the A/C MG relay from fuse and relay block 2. Does the A/C compressor clutch disengage? | Go to Step 5 | Go to Step 4
4 | Repair the short to voltage in the A/C compressor clutch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | --
5 | Test the A/C MG relay for continuity between terminals 3 and 5. Refer to Power and Grounding Component Views in Wiring Systems. Does continuity exist? | Go to Step 11 | Go to Step 6
6 |

1. Install the A/C MG relay.
2. Disconnect the A/C switch.

Does the A/C compressor clutch disengage?

Go to Step 12

Go to Step 7

7 |

1. Connect the A/C switch.
2. Disconnect the A/C compressor control module.

Does the A/C compressor clutch disengage?

Go to Step 9

Go to Step 8

8 | Repair the short to ground in the A/C MG relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | --
9 | Test for a short to voltage in the A/C compressor control module supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10
10 | Replace the A/C compressor control module. Refer to Air Conditioning (A/C) Compressor Control Module Replacement . Did you complete the replacement? | Go to Step 13 | --
11 | Replace the MG relay. Refer to Compressor Relay Replacement . Did you complete the replacement? | Go to Step 13 | --
12 | Replace the A/C switch. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3