Pinpoint Test Q: The Heated Seats Are Inoperative - Front

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.

WARNING: Never install heated seat parts not intended for use on this vehicle. Parts released for other model years or vehicle lines are not compatible even if they appear visually and physically similar. Installing incorrect parts will result in heated seat system performance outside design specification. Failure to follow this instruction may result in serious personal injury.

NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition is ON.

NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.

Q1 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE
- Ignition OFF.
- Depower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Disconnect: Passenger Seat Side Air Bag C327.
- Disconnect: Heated Seat Module C329.
- Connect the battery ground cable. Refer to BATTERY, MOUNTING AND CABLES .
- Ignition ON.
- Measure the voltage between:
  - heated seat module C329-2, circuit CBP35 (YE/GY), harness side and ground.
  - heated seat module C329-1, circuit SBB16 (VT/RD), harness side and ground.
    
    Fig 1: Measuring Voltage Between Heated Seat Module C329-2, Circuit CBP35 (YE/GY), Harness Side And Ground
    Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
- Yes: GO to Q2 .
- No: VERIFY Battery Junction Box (BJB) fuse 16 (30A) and Smart Junction Box (SJB) fuse 35 (10A) are OK. If OK, REPAIR the affected circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS for Edge or SYSTEM WIRING DIAGRAMS for MKX to identify possible causes of the circuit short. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
Q2 CHECK THE HEATED SEAT MODULE GROUND
- Ignition OFF.
- Measure the resistance between heated seat module C329-7, circuit GD133 (BK), harness side and ground.
  
  Fig 2: Measuring Resistance Between Heated Seat Module C329-7, Circuit GD133 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to Q3 .
- No: REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
Q3 CHECK THE SENSOR RETURN CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between heated seat module C329-13, circuit RHS05 (YE/VT), harness side and ground.
  
  Fig 3: Measuring Voltage Between Heated Seat Module C329-13, Circuit RHS05 (YE/VT), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes: REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- No: GO to Q4 .
Q4 CHECK THE SENSOR RETURN CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between heated seat module C329-13, circuit RHS05 (YE/VT), harness side and ground.
  
  Fig 4: Measuring Resistance Between Heated Seat Module C329-13, Circuit RHS05 (YE/VT), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms?
- Yes: GO to Q5 .
- No: REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
Q5 CHECK THE SENSOR RETURN CIRCUIT FOR AN OPEN
- Disconnect: Passenger Heated Seat C3284.
- Measure the resistance between heated seat module C329-13, circuit RHS05 (YE/VT), harness side and passenger heated seat C3284-3, circuit RHS05 (YE/VT), harness side.
  
  Fig 5: Measuring Resistance Between Heated Seat Module C329-13 And Passenger Heated Seat C3284-3
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: GO to Q6 .
- No: REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
Q6 CHECK THE HEATED SEAT GROUND
- Measure the resistance between heated seat C3284-4, circuit GD145 (BK/BU), harness side and ground.
  
  Fig 6: Measuring Resistance Between Heated Seat C3284-4, Circuit GD145 (BK/BU), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes: INSTALL a new heated seat module. REFER to HEATED SEAT MODULE - FRONT . TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- No: REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C327.
  
  CONNECT driver seat side air bag module C328.
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .