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Home >> Ford >> 2012 >> Explorer Base, 3.5 8, AWD, 6F50 >> Repair and Diagnosis >> External Pages >> Different car >> Section 189 (Windows And Glass - Glass, Frames And Mechanisms) >> Diagnosis And Testing >> Glass, Frames and Mechanisms >> Pinpoint Tests >> Pinpoint Test D: The Defrost System is Inoperative >> Pinpoint Test D: The Defrost System Is Inoperative

Pinpoint Test D: The Defrost System Is Inoperative

WARNING: This page is about a different car, the 2013 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. D1 CHECK THE REAR WINDOW DEFROST GRID VOLTAGE 
    • Disconnect: Rear Window Defrost Grid Power C402A (Coupe) or C402 (Convertible).
    • Start the engine.
    • Activate the rear window defrost switch and measure the voltage between rear window defrost grid power C402A-1 (coupe) or C402-1 (convertible), circuit CRD17 (GY), harness side and ground.
      Fig 1: Measuring Voltage Between Rear Window Defrost Grid Power C402A-1 (Coupe) Circuit CRD17 (GY)
      G06403946Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. Yes  : GO to D2.
    2. No  : GO to  D3.
  2. D2 CHECK THE REAR WINDOW DEFROST GRID GROUND 
    • Ignition OFF.
    • Disconnect: Rear Window Defrost Grid Ground C402B (Coupe).
    • Measure the resistance between rear window defrost grid ground C402B-1 (coupe), circuit GD109 (BK), harness side and ground; or between C402-2 (convertible), circuit GD110 (BK/WH), harness side and ground.
      Fig 2: Measuring Resistance Between Rear Window Defrost Grid Ground C402B-1 (Coupe), Circuit GD109 (BK) And Ground
      G06403947Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    1. Yes  : CARRY OUT the GRID WIRE TEST . REPAIR the rear window defrost grid or INSTALL a new rear window glass. REFER to WINDOW GRID WIRE REPAIR . CLEAR the DTCs. TEST the system for normal operation.
    2. No  : REPAIR the circuit. TEST the system for normal operation.
  3. D3 CHECK THE POWER TO THE RELAY 
    • Ignition OFF.
    • Disconnect: Rear Window Defrost Relay.
    • Ignition ON.
    • Measure the voltage between rear window defrost relay socket pin 86, circuit CBP37 (WH), harness side and ground; and between rear window defrost relay socket pin 30, circuit SBB06 (BN/RD), harness side and ground.
      Fig 3: Measuring Voltage Between Rear Window Defrost Relay Socket Pin 86, Circuit CBP37 (WH) And Ground
      G06403948Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts for both measurements? 
    1. Yes  : GO to D4.
    2. No  : VERIFY Battery Junction Box (BJB) fuse 6 (30A) and SJB fuse 37 (10A) are OK. If OK, REPAIR the circuit(s). CLEAR the DTCs. TEST the system for normal operation.

      If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible causes of the circuit short.

      REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.

  4. D4 CHECK THE HVAC MODULE 
    • Start the engine.
    • Activate the rear window defrost switch.
    • NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the SPECIAL TOOLS  or equivalent. 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.

      Connect a 12-volt incandescent test light between rear window defrost relay socket pin 85, circuit CH122 (WH/OG), harness side and rear window defrost relay socket pin 86, circuit CBP37 (WH), harness side.

      Fig 4: Connecting 12-Volt Incandescent Test Light Between Rear Window Defrost Relay Socket Pin 85, Circuit CH122 (WH/OG)
      G06070957Courtesy of FORD MOTOR CO.
    • Does the test light illuminate? 
    1. Yes  : GO to D5.
    2. No  : GO to  D6.
  5. D5 CHECK THE REAR WINDOW DEFROST RELAY 
    • Carry out the rear window defrost relay component test. Refer to appropriate OEM WIRING COMPONENT TESTING for component testing .
    • Did the rear window defrost relay pass the component test? 
    1. Yes  : REPAIR open in circuit CRD17 (GY). CLEAR the DTCs. TEST the system for normal operation.
    2. No  : INSTALL a new rear window defrost relay. CLEAR the DTCs. TEST the system for normal operation.
  6. D6 CHECK THE REAR WINDOW DEFROST SWITCH (CC_SW_R_DEF) PID 
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: DataLogger - FCIM.
    • Monitor the FCIM CC_SW_R_DEF PID while pressing and releasing the rear window defrost switch.
    • Does the PID agree with the rear window defrost switch status? 
    1. Yes  : GO to D7.
    2. No  : INSTALL a new FCIM. CLEAR the DTCs. TEST the system for normal operation.
  7. D7 CHECK CIRCUIT CH122 (WH/OG) FOR AN OPEN 
    • Ignition OFF.
    • Disconnect: HVAC module C294A.
    • Measure the resistance between rear window defrost relay socket pin 85, circuit CH122 (WH/OG), harness side and HVAC module C294A-2, circuit CH122 (WH/OG), harness side.
      Fig 5: Measuring Resistance Between Rear Window Defrost Relay Socket Pin 85, Circuit CH122 (WH/OG) And HVAC Module C294A-2
      G07477228Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    1. Yes  : GO to D8.
    2. No  : REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
  8. D8 CHECK FOR CORRECT HVAC MODULE OPERATION 
    • Disconnect all HVAC module electrical connectors.
    • Check for:
      • corrosion.
      • pushed-out pins.
    • Connect all HVAC module electrical connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. Yes  : INSTALL a new HVAC module. TEST the system for normal operation.
    2. No  : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
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