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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1548 (Windows And Glass - Glass, Frames And Mechanisms) >> Diagnosis And Testing >> Glass, Frames and Mechanisms >> Pinpoint Tests >> Pinpoint Test F: The Defrost System is Inoperative >> Pinpoint Test F: The Defrost System Is Inoperative

Pinpoint Test F: The Defrost System Is Inoperative

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. F1 CHECK CIRCUIT CRD06 (BN/YE) FOR VOLTAGE 
    • Disconnect: Rear Window Defrost Grid C402A.
    • Start the engine.
    • Activate the rear window defrost switch.
    • Measure the voltage between rear window defrost grid C402A-1, circuit CRD06 (BK), harness side and ground.
      Fig 1: Measuring Voltage Between Rear Window Defrost Grid C402A-1, Circuit CRD06 (BN/YE), Harness Side And Ground
      G06070954Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  GO to F2  .
    • No:  VERIFY BJB  fuse 2 (30A) is OK. If OK, GO to  F3.

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

  2. F2 CHECK THE GRID GROUND CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Disconnect: Rear Window Defrost C402B.
    • Measure the resistance between rear window defrost grid C402B-1, circuit GD149 (BK/GY), harness side and ground.
      Fig 2: Measuring Resistance Between Rear Window Defrost Grid Ground C402B-1, Circuit GD173 (BK) And Ground
      G06070955Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  CARRY OUT the Grid Wire Component Test. REPAIR the rear window defrost grid or INSTALL a new liftgate glass as necessary. REFER to WINDOW GRID WIRE REPAIR  or WINDOW GLASS - LIFTGATE . TEST the system for normal operation.
    • No:  REPAIR the circuit. CLEAR all DTCs. TEST the system for normal operation.
  3. F3 CHECK THE REAR WINDOW DEFROST RELAY FEED CIRCUITS FOR VOLTAGE 
    • Ignition OFF.
    • Disconnect: Rear Window Defrost Relay.
    • Ignition ON.
    • Measure the voltage between rear window defrost relay socket pin 3, circuit CBB35 (YE/GY) and ground; and between rear window defrost socket relay socket pin 1, circuit CBB35 (YE/GY) and ground.
      Fig 3: Checking Rear Window Defrost Relay Feed Circuits For Voltage
      G06099734Courtesy of FORD MOTOR CO.
    • Are the voltages greater than 10 volts? 
    • Yes:  GO to F4  .
    • No:  VERIFY BJB  fuse 35 (10A) is OK. If OK, REPAIR the circuit.

      If not OK, REFER to appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short. CLEAR all DTCs. TEST the system for normal operation.

  4. F4 CHECK THE HVAC MODULE 
    NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the SPECIAL TOOL CHART . 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.
    • Start the engine.
    • Activate the rear window defrost switch.
    • Connect a 12-volt incandescent test light between rear window defrost relay socket pin 2, circuit CH122 (WH/OG) and rear window defrost relay socket pin 1, circuit CBB35 (YE/GY).
      Fig 4: Connecting 12-Volt Incandescent Test Light Between Rear Window Defrost Relay Socket Pin 2 And Rear Window Defrost Relay Socket Pin 1
      G06391389Courtesy of FORD MOTOR CO.
    • Does the test light illuminate? 
    • Yes:  GO to F5  .
    • No:  For Escape Hybrid equipped with navigation only, GO to  F6. For all other vehicles, GO to  F7.
  5. F5 CHECK THE REAR WINDOW DEFROST RELAY 
    • Ignition OFF.
    • Carry out the rear window defrost relay component test.

      Refer to COMPONENT TESTING for component testing.

    • Did the rear window defrost relay pass the component test? 
    • Yes:  REPAIR open in circuit CRD06 (BN/YE). CLEAR the DTCs. TEST the system for normal operation.
    • No:  INSTALL a new rear window defrost relay. CLEAR all DTCs. TEST the system for normal operation.
  6. F6 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? 
    • Yes:  GO to F7  .
    • No:  INSTALL a new FCIM  . CLEAR the DTCs. TEST the system for normal operation.
  7. F7 CHECK CIRCUIT CH122 (WH/OG) FOR AN OPEN 
    • Ignition OFF.
    • Disconnect: HVAC Module - Electronic Manual Temperature Control (EMTC) C2357A or HVAC Module - Dual Automatic Temperature Control (DATC) C2356A.
    • Measure the resistance between rear window defrost relay socket pin 2, circuit CH122 (WH/OG) and HVAC module EMTC C2357A-3, HVAC module - DATC  C2356A-3 (non-hybrid) or C2356A-12 (hybrid), circuit CH122 (WH/OG), harness side.
      Fig 5: Measuring Resistance Between Rear Window Defrost Relay Socket Pin 2 And HVAC Module EMTC C2357A-3
      G06391390Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to F8  .
    • No:  REPAIR the circuit. CLEAR all DTCs. TEST the system for normal operation.
  8. F8 CHECK FOR CORRECT HVAC MODULE OPERATION 
    • Disconnect all the HVAC module connectors.
    • Check for:
      • corrosion.
      • pushed-out pins.
    • Connect all the HVAC module connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    • Yes:  INSTALL a new HVAC module. REFER to MULTIFUNCTION ELECTRONIC MODULES . 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 all DTCs. TEST the system for normal operation.
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