Pinpoint Test T: The Heated Seat Is Inoperative - Driver Seat Does Heat But The Heated Seat Indicator Does Not Illuminate When Pressed

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.

T1 CHECK CIRCUITS CHS04 (YE/GY) AND CHS13 (VT/BN) FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS . Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Disconnect: Passenger Seat Side Air Bag C327.
- Disconnect: HVAC Module C228b.
- Disconnect: Heated Seat Module C329.
- Connect the battery ground cable. Refer to BATTERY, MOUNTING AND CABLES .
- Measure the resistance between:
  - HVAC module C228b-7, circuit CHS04 (YE/GY), harness side and ground.
  - HVAC module C228b-8, circuit CHS13 (VT/BN), harness side and ground.
    
    Fig 1: Measuring Resistance Between HVAC Module C228B-7, Circuit CHS04 (YE/GY), Harness Side And Ground
    Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,000 ohms?
- Yes: GO to T2 .
- No: REPAIR the affected 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 .
T2 CHECK CIRCUITS CHS04 (YE/GY) AND CHS13 (VT/BN) FOR AN OPEN
- Measure the resistance between:
  - HVAC module C228b-7, circuit CHS04 (YE/GY), harness side and heated seat module C329-5, circuit CHS04 (YE/GY), harness side.
  - HVAC module C228b-8, circuit CHS13 (VT/BN), harness side and heated seat module C329-4, circuit CHS13 (VT/BN), harness side.
    
    Fig 2: Measuring Resistance Between HVAC Module C228B-7 And Heated Seat Module C329-5
    Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: GO to T3 .
- No: REPAIR the affected 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 .
T3 CHECK THE HEATED SEAT MODULE HI INDICATOR ON THE HVAC MODULE
- Connect: HVAC Module C228b.
- Ignition ON.
- Connect a fused jumper lead between heated seat module C329-4, circuit CHS13 (VT/BN), harness side and C329-1, circuit SBB16 (VT/RD), harness side.
  
  Fig 3: Connecting Fused Jumper Lead Between Heated Seat Module C329-4, Circuit CHS13 (VT/BN) And C329-1, Circuit SBB16 (VT/RD)
  Courtesy of FORD MOTOR CO.
- Does the right driver heated seat indicator LED illuminate on the HVAC module?
- Yes: GO to T4 .
- No: INSTALL a new HVAC module. REFER to CLIMATE CONTROL . 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 .
T4 CHECK THE HEATED SEAT MODULE LOW INDICATOR ON THE HVAC MODULE
- Connect a fused jumper lead between heated seat module C329-5, circuit CHS04 (YE/GY), harness side and C329-1, circuit SBB16 (VT/RD), harness side.
  
  Fig 4: Connecting Fused Jumper Lead Between Heated Seat Module C329-5, Circuit CHS04 (YE/GY) And C329-1, Circuit SBB16 (VT/RD)
  Courtesy of FORD MOTOR CO.
- Does the left driver heated seat indicator LED illuminate on the HVAC module?
- 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: INSTALL a new HVAC module. REFER to CLIMATE CONTROL . 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 .