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

WARNING: This page is about a different car, the 2010 Lincoln MKX and 2010 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

N1 CHECK THE AIR CONDITIONING COMPRESSOR CYCLING SWITCH (ACCS) PCM PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: ACCS PCM PID.
- Select the OFF position on the HVAC module.
- Does the ACCS PCM PID read ON?
- Yes: For DATC systems, GO to N2 .
  For EMTC systems, GO to N3.
- No: GO to N6.
N2 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_AC) HVAC PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: CC_AC HVAC PID.
- Select the OFF position on the HVAC module.
- Does the CC_AC HVAC PID read ON?
- Yes: GO to N5.
- No: GO to N6.
N3 CHECK HVAC - EMTC A/C REQUEST OUTPUT
NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the SPECIAL TOOL REFERENCE table . To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: IC C220.
- Ignition ON.
- Select the OFF position on the HVAC module - EMTC .
- Connect a 12-volt test light between IC C220-23, circuit CH434 (GY/YE), harness side and IC C220-19, circuit SBP26 (YE/RD), harness side.
  
  Fig 1: Connecting 12-Volt Test Light Between IC C220-23, Circuit CH434 (GY/YE) And IC C220-19, Circuit SBP26 (YE/RD)
  Courtesy of FORD MOTOR CO.
- Does the test light illuminate?
- Yes: GO to N6.
- No: GO to N4 .
N4 CHECK CIRCUIT CH434 (GY/YE) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C2357A.
- Measure the resistance between IC C220-23, circuit CH434 (GY/YE), harness side and ground.
  
  Fig 2: Measuring Resistance Between IC C220-23, Circuit CH434 (GY/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes: GO to N5 .
- No: REPAIR circuit CH434 (GY/YE) for a short to ground. TEST the system for normal operation.
N5 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC 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 . 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
N6 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.