Pinpoint Test Q: The Air Conditioning (A/C) Is Always On - A/C Mode Always Commanded ON

Climate Control System

Pinpoint Test Q: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON

Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number

Normal Operation

Under normal operation, when A/C is requested, the HVAC module sends an A/C request message over the Standard Corporate Protocol (SCP) bus to the Instrument Cluster (IC), then from the IC through the High Speed Controller Area Network (HS-CAN) bus to the PCM.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM
- A/C clutch relay
- HVAC module
- A/C clutch air gap


PINPOINT TEST Q: THE AIR CONDITIONING (A/C) IS ALWAYS ON - A/C MODE ALWAYS COMMANDED ON

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Q1 CHECK THE AIR CONDITIONING SWITCH STATUS (AC_SEL_SW) HVAC PID WITH THE A/C OFF


- Ignition ON.
- Press the OFF manual override button on the HVAC module.
- Enter the following diagnostic mode on the scan tool: AC_SEL_SW HVAC PID.
- Does the AC_SEL_SW HVAC PID read NOT PRESSED?

Yes
GO to Q3.

No
GO to Q2.

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Q2 CHECK THE HVAC MODULE CONNECTION


- Inspect the module connectors for:

- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new HVAC module. REFER to Climate Control Service and Repair. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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Q3 CHECK THE PCM CONNECTION


- Disconnect all the PCM connectors.
- Inspect the module connectors for:

- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the PCM connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new PCM. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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