Pinpoint Test Q: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON
Climate Control System
Pinpoint Tests
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. 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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