Pinpoint Test H: The Air Conditioning (A/C) Is Always On - A/C Mode Always Commanded ON
Climate Control System
Pinpoint Tests
Pinpoint Test H: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON
Refer to Wiring Diagram Set 55 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, voltage is supplied to the A/C low charge protection switch through circuit CBK03 (GY). When the A/C low charge protection switch is closed (ON, pressure normal), voltage is sent to the dual-function pressure switch through circuit CH422 (VT). When the dual-function pressure switch is closed (ON, pressure normal), voltage is provided to the PCM. Ignition voltage is provided to the A/C clutch relay switch through circuit SBB13 (GY/RD). When A/C is requested, a message is sent over the Medium Speed Controller Area Network (MS-CAN) bus to the PCM. When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD123 (BK/GY).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PCM
- HVAC module
- A/C low charge protection switch
PINPOINT TEST H: THE AIR CONDITIONING (A/C) IS ALWAYS ON - A/C MODE ALWAYS COMMANDED ON
NOTE: Before carrying out the following test, diagnose any PCM or Instrument Cluster (IC) DTCs.
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H1 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_AC) HVAC PID WITH THE A/C OFF
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: CC_AC HVAC PID.
- Select PANEL mode on the HVAC module and make sure the A/C button and indicator are OFF.
- Does the CC_AC HVAC PID read OFF?
Yes
GO to H2.
No
GO to H5.
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H2 CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PCM PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: AC_REQ PCM PID.
- Select PANEL mode on the HVAC module and make sure the A/C button and indicator are OFF.
- Does the AC_REQ PCM PID read OFF?
Yes
GO to H3.
No
GO to H6.
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H3 CHECK THE AIR CONDITIONING CLUTCH ALLOWED (ACCLT_ALW) PCM PID
- Ignition OFF.
- Disconnect: Dual-Function Pressure Switch C1062.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ACCLT_ALW PCM PID.
- Press the PANEL and A/C manual override buttons (A/C indicator ON) on the HVAC module.
- Does the ACCLT_ALW PCM PID read YES?
Yes
REPAIR circuit CH421 (GY) for a short to voltage. TEST the system for normal operation.
No
GO to H4.
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H4 CHECK THE A/C COMPRESSOR OPERATION
- Ignition OFF.
- Connect: Dual-Function Pressure Switch C1062.
- Disconnect: Low Charge Protection Switch C130.
- With the engine running, press the PANEL and A/C manual override buttons on the HVAC module.
- Does the A/C compressor operate?
Yes
GO to H6.
No
INSTALL a new A/C low charge protection switch. TEST the system for normal operation.
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H5 CHECK THE MODULE CONNECTION
- Ignition OFF.
- Disconnect all the HVAC module connectors.
- Check for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- 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. TEST the system for normal operation.
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H6 CHECK THE PCM MODULE CONNECTION
- Clear the DTCs.
- Disconnect all of the PCM connectors.
- Check for:
- corrosion.
- pushed-out connectors/pins.
- incorrectly seated connector.
- Connect and correctly seat all of the PCM connectors.
- Operate the system.
- Does the concern return?
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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