Pinpoint Test O: The Heated Seat Is Inoperative - Front Passenger

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If a seat equipped with a seat mounted side air bag is being repaired, 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.

O1 CHECK FOR HVAC DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
Were any DTCs retrieved during the self-tests?
- Yes : For DTCs B1036:11 or B1036:13, GO to O3.
  For DTCs B103A:11 or B103A:12, GO to O4.
  
  For all other DTCs, REFER to the HVAC MODULE DTC CHART .
- No : GO to O2 .
O2 CHECK THE TOUCHSCREEN CONTROLS OPERATION
- Start the engine.
- Select each audio and climate control function using the touchscreen controls.
Do all touchscreen controls operate?
- Yes : GO to O3 .
- No : REFER to INFORMATION AND ENTERTAINMENT SYSTEMS - 8-INCH (203MM) TOUCHSCREEN or INFORMATION AND ENTERTAINMENT SYSTEMS - SONY 8-INCH TOUCHSCREEN to diagnose the inoperative touchscreen.
O3 CHECK THE HEATER ELEMENT POWER CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Depower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Passenger Seat Side Air Bag Module C339 .
- Disconnect: HVAC Module C228B.
- Disconnect: Passenger Cushion Heater Mat C334.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any airbag 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 .
- Measure the resistance between:
  - passenger seat cushion heater mat C334-1 , circuit CHS07 (GY/BU), harness side and ground.
  - passenger seat cushion heater mat C334-1 , circuit CHS07 (GY/BU), harness side and HVAC module C228B-17 , circuit CHS07 (GY/BU), harness side.
    
    Fig 1: Measuring Resistance Between Passenger Seat Cushion Heater Mat C334-1, Circuit CHS07 (GY/BU) And Ground
    Courtesy of FORD MOTOR CO.
Is the resistance greater than 10, 000 ohms between the passenger seat cushion heater mat and ground; and less than 3 ohms between the passenger seat cushion heater mat and the HVAC module?
- Yes : GO to O7.
- No : REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O4 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Depower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Passenger Seat Side Air Bag Module C339 .
- Disconnect: HVAC Module C228B.
- Disconnect: Passenger Cushion Heater Mat C334.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any airbag 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 .
- Measure the resistance between:
  - passenger seat cushion heater mat C334-2 , circuit VHS27 (WH/OG), harness side and ground.
  - passenger seat cushion heater mat C334-2 , circuit VHS27 (WH/OG), harness side and HVAC module C228B-15 , circuit VHS27 (WH/OG), harness side.
    
    Fig 2: Measuring Resistance Between Passenger Seat Cushion Heater Mat C334-2, Circuit VHS27 (WH/OG) And Ground
    Courtesy of FORD MOTOR CO.
Is the resistance greater than 10, 000 ohms between the passenger seat cushion heater mat and ground; and less than 3 ohms between the passenger seat cushion heater mat and the HVAC module?
- Yes : GO to O5 .
- No : REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O5 CHECK THE HEATED SEAT TEMPERATURE SENSOR RETURN CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Disconnect: HVAC Module C228A.
- Measure the resistance between:
  - passenger seat cushion heater mat C334-3 , circuit RHS05 (YE/VT), harness side and ground.
  - passenger seat cushion heater mat C334-3 , circuit RHS05 (YE/VT), harness side and HVAC module C228A-23 , circuit RH111 (GY/BU), harness side.
    
    Fig 3: Measuring Resistance Between Passenger Seat Cushion Heater Mat C334-3, Circuit RHS05 (YE/VT) And Ground
    Courtesy of FORD MOTOR CO.
Is the resistance greater than 10, 000 ohms between the passenger seat cushion heater mat and ground; and less than 3 ohms between the passenger seat cushion heater mat and the HVAC module?
- Yes : GO to O6 .
- No : REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O6 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between the following passenger seat cushion heater mat C334-2 , circuit VHS27 (WH/OG), harness side and ground.
  
  Fig 4: Measuring Voltage Between Passenger Seat Cushion Heater Mat C334-2, Circuit VHS27 (WH/OG) 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 C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- No : GO to O11.
O7 CHECK THE HEATER ELEMENT GROUND CIRCUIT FOR AN OPEN
- Disconnect: Passenger Seat Backrest Heater Mat C335 .
- Measure the resistance between passenger seat backrest heater mat C335-2 , circuit GD904 (BK/BU), harness side and ground.
  
  Fig 5: Measuring Resistance Between Passenger Seat Backrest Heater Mat C335-2, Circuit GD904 (BK/BU) And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance less than 0.5 ohms?
- Yes : GO to O8 .
- No : REPAIR the circuit. TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O8 CHECK CUSHION HEATED SEAT MAT FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between passenger seat cushion heater mat C334 pins 1 and 4, component side; and between passenger seat cushion heater mat C334 pin 1, component side and ground.
  
  Fig 6: Measuring Resistance Between Passenger Seat Cushion Heater Mat C334 Pin 1 And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance between 0.6 and 2 ohms between pins 1 and 4; and greater than 10, 000 ohms between pin 1 and ground?
- Yes : GO to O9 .
- No : INSTALL a new passenger seat cushion heater mat. REFER to SEAT CUSHION HEATER MAT - FRONT . TEST the system for normal operation. DISCONNECT the battery ground cable.
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O9 CHECK THE BACKREST HEATED SEAT MAT FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between passenger seat backrest heater mat C335 pins 1 and 2, component side; and between passenger seat backrest heater mat C335 pin 2, component side and ground.
  
  Fig 7: Measuring Resistance Between Passenger Seat Backrest Heater Mat C335 Pin 2 And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance between 0.9 and 1.1 ohms between pins 1 and 2: and greater than 10, 000 ohms between pin 2 and ground?
- Yes : GO to O10 .
- No : INSTALL a new passenger front seat backrest heater mat. REFER to SEAT BACKREST HEATER MAT - FRONT . TEST the system for normal operation. DISCONNECT the battery ground cable.
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O10 CHECK THE CIRCUIT BETWEEN THE CUSHION HEATER MAT AND BACKREST HEATER MAT FOR AN OPEN AND SHORT TO GROUND
- Measure the resistance between:
  - passenger seat cushion heater mat C334-4 , circuit CHS01 (GY/VT), harness side and seat backrest heater mat C365-1 , circuit CHS01 (GY/VT) harness side.
  - passenger seat cushion heater mat C334-4 , circuit CHS01 (GY/VT), harness side and ground.
    
    Fig 8: Measuring Resistance Between Passenger Seat Cushion Heater Mat C334-4, Circuit CHS01 (GY/VT) And Ground
    Courtesy of FORD MOTOR CO.
Is the resistance less than 3 ohms between C334-4 and C335-1, and greater than 10, 000 ohms between C334-4 and ground?
- Yes : INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE . TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  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 C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
O11 CHECK THE HEATED SEAT TEMPERATURE SENSOR FOR AN OPEN OR SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between passenger heated seat cushion C334 pins 2 and 3, component side; and between heated seat cushion C334 pin 2, component side and ground.
  
  Fig 9: Measuring Resistance Between Heated Seat Cushion C334 Pin 2 And Ground
  Courtesy of FORD MOTOR CO.
Is the resistance between 300 ohms and 300, 000 ohms between pins 2 and 3; and greater than 10, 000 ohms between pin 2 and ground?
- Yes : INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE . TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- No : INSTALL a new cushion heater mat. REFER to SEAT CUSHION HEATER MAT - FRONT . TEST the system for normal operation.
  DISCONNECT the battery ground cable.
  
  CONNECT passenger seat side air bag module C339 .
  
  REPOWER the SRS . REFER to SUPPLEMENTAL RESTRAINT SYSTEM .