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Pinpoint Test Q: The Heated Seats Are Inoperative - Driver And Front Passenger

NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS fault.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
  1. Q1 CHECK HEATED SEAT OPERATION 
    • Ignition OFF.
    • Start the engine.
    • Verify both heated seats do not heat.
    • Does either heated seat operate? 
      • Yes:  GO to Symptom Chart  to diagnose the heated seat is inoperative/does not operate correctly - driver or the heated seat is inoperative/does not operate correctly - passenger.
      • No:  GO to  Q2.
  2. Q2 CHECK HEATED SEAT INDICATOR ILLUMINATION 
    • Ignition OFF.
    • Start the engine.
    • Verify system indicator illumination.
    • When pressing and releasing each heated seat button individually, does any heated seat indicator illuminate or flash and then turn off? 
      • Yes:  GO to  Q7.
      • No:  For vehicles with navigation, GO to  Q3.

        For vehicles without navigation, GO to  Q4.

  3. Q3 RETRIEVE THE FCIM DTCs 
    • Enter the following diagnostic mode on the scan tool: Self Test - FCIM.
    • Are any FCIM DTCs retrieved? 
  4. Q4 RETRIEVE THE HVAC MODULE DTCs 
    • Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
    • Are any HVAC module DTCs retrieved? 
      • Yes:  For any HVAC module DTCs, REFER to the HVAC Module DTC Chart  .
      • No:  For vehicles with navigation, GO to  Q5.

        For vehicles without navigation, GO to  Q6.

  5. Q5 MONITOR THE FCIM PIDs AND CHECK INPUTS 
    • Enter the following diagnostic mode on the scan tool: DataLogger - FCIM- PIDs.
      • Driver Heated Seat (CC_SW_D_HSEATS)
      • Passenger Heated Seat (CC_SW_P_HSEATS)
    • Monitor the FCIM PIDs while individually pushing the driver and passenger heated seat buttons.
    • Do the PID values agree with the switch button positions? 
  6. Q6 MONITOR THE HVAC MODULE PIDs AND CHECK INPUTS 
    • Enter the following diagnostic mode on the scan tool: DataLogger - HVAC Module - PIDs.
      • Driver Heated Seat (CC_SW_D_HSEATS)
      • Passenger Heated Seat (CC_SW_P_HSEATS)
    • Monitor HVAC module PIDs while individually pushing the driver and passenger heated seat buttons.
    • Do the PID values agree with the switch button positions? 
      • Yes:  The fault is intermittent, CHECK for causes of the intermittent fault. INSPECT the connectors, terminals and wiring. ATTEMPT to recreate the fault by flexing the wire harness and operating the system. CHECK the electrical connectors for corrosion, poor pin contact or pushed-out pins. REPAIR any intermittent concerns found and TIGHTEN any loose connector pins. REPEAT the self-test. CLEAR the DTCs. CHECK the system for normal operation.
      • No:  INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
  7. Q7 CHECK VOLTAGE TO THE HEATED SEAT MODULE 
    • Ignition OFF.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of SUPPLEMENTAL RESTRAINT SYSTEM .
    • Disconnect: Passenger Seat Side Air Bag Module C313.
    • Disconnect: Heated Seat Module C3304B.
      • WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
    • Connect the battery ground cable. Refer to BATTERY, MOUNTING AND CABLES .
    • Ignition ON.
    • Measure the voltage between:
      • heated seat module C3304B-1, circuit SBP18 (YE/RD), harness side and ground.
      • heated seat module C3304B-2, circuit CBP35 (YE/GY), harness side and ground.
      Fig 1: Checking Voltage To Heated Seat Module
      G06063252Courtesy of FORD MOTOR CO.
    • Are the voltages greater than 10 volts? 
      • Yes:  GO to  Q8.
      • No:  VERIFY Smart Junction Box (SJB) fuses 18 (20A) and 35 (10A) are OK. If OK, REPAIR the affected circuit. If not OK, REFER to the Wiring Diagrams information to identify the possible causes of the circuit short. TEST the system for normal operation.

        DISCONNECT the battery ground cable.

        CONNECT passenger seat side air bag module C313.

        REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  8. Q8 CHECK THE HEATED SEAT MODULE GROUND CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between heated seat module C3304B-5, circuit GD139 (BK/YE), harness side and ground.
      Fig 2: Checking Heated Seat Module Ground Circuit For Open
      G06063253Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
      • Yes:  GO to  Q9.
      • No:  REPAIR the circuit. TEST the system for normal operation.

        DISCONNECT the battery ground cable.

        CONNECT passenger seat side air bag module C313.

        REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

  9. Q9 CHECK HEATED SEAT MODULE SENSOR RETURN CIRCUIT FOR AN OPEN 
    • Disconnect: Heated Seat Module C3304A.
    • Disconnect: Passenger Seat Cushion Heater C334.
    • Measure the resistance between heated seat module C3304A-12, circuit RHS05 (YE/VT), harness side and passenger seat cushion heater C334-4, circuit RHS05 (YE/VT), harness side.
      Fig 3: Checking Heated Seat Module Sensor Return Circuit For Open
      G06259276Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
      • Yes:  INSTALL a new heated seat module. REFER to Heated Seat Module  . TEST the system for normal operation.

        DISCONNECT the battery ground cable.

        CONNECT passenger seat side air bag module C313.

        REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

      • No:  REPAIR the circuit. TEST the system for normal operation.

        DISCONNECT the battery ground cable.

        CONNECT passenger seat side air bag module C313.

        REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .

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