Pinpoint Test A: The Heated Seats Are Inoperative

NOTE: Several heated seat circuits change circuit numbers and wire colors at the seat-to-body electrical connectors. Be sure circuits are tested as described in this procedure for correct diagnosis.

A1 CHECK OPERATION OF THE HEATED SEAT INDICATORS
- Start the engine.
- Verify the HVAC module operates by checking other climate control system features.
- Press both heated seat switches to on.
- Does the HVAC module operate and do both heated seat switch indicators illuminate?
  - Yes : GO to A2.
  - No : REFER to DIAGNOSIS AND TESTING article to diagnose any climate control system concerns. Otherwise, INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE article. TEST the system for normal operation.
A2 CHECK THE HVAC MODULE FOR HEATED SEAT DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Are any DTCs retrieved?
  - Yes : REFER to the HVAC MODULE DTC CHART .
  - No : GO to A3.
A3 CHECK THE HEATED SEAT RELAY CIRCUITS FOR VOLTAGE
- Ignition OFF.
- Depower the Supplemental Restraint System (SRS). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of DEPOWERING PROCEDURE article.
- Disconnect: Driver Seat Side Air Bag C367 or Passenger Seat Side Air Bag C337.
- Disconnect: Driver Safety Belt Buckle and Pretensioner C3201 or Passenger Safety Belt Buckle and Pretensioner C3202.
- Disconnect: Driver Heated Seat Relay C3260 or Passenger Heated Seat Relay C3261.
- 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, BATTERY MOUNTING & BATTERY CABLES article.
- Ignition ON.
- For driver seat, measure the voltage between:
  - heated seat relay C3260-3, circuit CHS02 (YE/BU), harness side and ground.
  - heated seat relay C3260-1, circuit VHS35 (VT/OG), harness side and ground.
  Fig 1: Checking Heated Seat Relay For Voltage (For Driver Seat)
  Courtesy of FORD MOTOR CO.
- For passenger seat, measure the voltage between:
  - heated seat relay C3261-3, circuit CHS02 (YE/BU), harness side and ground.
  - heated seat relay C3261-2, circuit SBX06 (GY/RD), harness side and ground.
  Fig 2: Checking Heated Seat Relay For Voltage (For Passenger Seat)
  Courtesy of FORD MOTOR CO.
- Are the voltages greater than 10 volts?
  - Yes : INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE article. TEST the system for normal operation.
  - No : VERIFY SJB fuses 18 (20A) and 43 (10A) are OK. If OK, REPAIR the circuit(s). If SJB fuse 18 (20A) is not OK, GO to A4 to check the heater circuits. TEST the system for normal operation.
    DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
    
    REPOWER the SRS. REFER to REPOWERING PROCEDURE article.
A4 CHECK THE HEATER CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Driver Cushion Heater Mat C364 and Passenger Cushion Heater Mat C334.
- Measure the resistance between:
  - driver heated seat relay C3260-5, circuit CHS11 (VT/GN), harness side and ground.
  - passenger heated seat relay C3261-5, circuit CHS07 (GY/BU), harness side and ground.
  Fig 3: Checking Heater Circuits For Short To Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10, 000 ohms?
  - Yes : GO to A5.
  - No : REPAIR the circuit(s). TEST the system for normal operation.
  DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
  
  REPOWER the SRS. REFER to REPOWERING PROCEDURE article.
A5 CHECK THE HEATER MATS FOR A SHORT TO GROUND
- Disconnect: Driver and Passenger Backrest Heater Mat Electrical Connectors.
- Occupy the seat while carrying out the following measurements.
- To check cushion heater mats, measure the resistance between:
  - driver cushion heater mat C364 pin 1, component side and ground.
  - driver cushion heater mat C364 pin 2, component side and ground.
  - passenger cushion heater mat C334 pin 1, component side and ground.
  - passenger cushion heater mat C334 pin 2, component side and ground.
  Fig 4: Measuring Resistance Between Driver Cushion Heater Mat C364 Pin 1, Component Side And Ground
  Courtesy of FORD MOTOR CO.
- To check backrest heater mats, measure the resistance between:
  - driver backrest heater mat connector pin 1, component side and ground.
  - passenger backrest heater mat connector pin 1, component side and ground.
  Fig 5: Measuring Resistance Between Driver Backrest Heater Mat Connector Pin 1, Component Side And Ground
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10, 000 ohms?
  - Yes : CHECK the heated seat wiring, heater mats and connector pins for damage and REPAIR as needed. TEST the system for normal operation.
    DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
    
    REPOWER the SRS. REFER to REPOWERING PROCEDURE article.
  - No : INSTALL a new cushion or backrest heater mat. REFER to SEAT BACKREST HEATER MAT or SEAT CUSHION HEATER MAT . TEST the system for normal operation.
    DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle and pretensioner C3201 or passenger seat safety belt buckle and pretensioner C3202 and driver seat side air bag C367 or passenger seat side air bag C337.
    
    REPOWER the SRS. REFER to REPOWERING PROCEDURE article.