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Pinpoint Test R: The Heated Seat Is Inoperative - Left Rear

WARNING: This page is about a different car, the 2012 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
  1. R1 CHECK THE HEATED SEAT OPERATION 
    • Ignition ON.
    • Operate the left rear heated seat switch.
    • Does the seat operate in either setting? 
      1. Yes  : If only the low setting operates, GO to  R15.

        If only the high setting operates, GO to  R16.

      2. No  : GO to R2.
  2. R2 CHECK THE HEATED SEAT SWITCH INPUT 
    • Ignition OFF.
    • For electrical connector access, release and lower the rear 60 percent seat backrest. Refer to the appropriate steps in HEATED SEAT MODULE - REAR  .
    • Disconnect: Rear Heated Seat Module C3162A.
    • Measure the resistance between rear heated seat module C3162A-2, circuit CHS46 (YE/GN), harness side and ground while pressing the heated seat switch to high.
      Fig 1: Measuring Resistance Between Rear Heated Seat Module C3162A-2, Circuit CHS46 (YE/GN), Harness Side And Ground
      G06076861Courtesy of FORD MOTOR CO.
    • Is the resistance less than 30 ohms when the switch is pressed and greater than 10, 000 ohms when not pressed? 
      1. Yes  : GO to  R4.
      2. No  : GO to R3.
  3. R3 CHECK THE HEATED SEAT SWITCH GROUND CIRCUIT FOR AN OPEN 
    • Disconnect: Left Rear Heated Seat Switch C731.
    • Measure the resistance between left rear heated seat switch C731-6, circuit GD139 (BK/YE), harness side and ground.
      Fig 2: Measuring Resistance Between Left Rear Heated Seat Switch C731-6, Circuit GD139 (BK/YE), Harness Side And Ground
      G06458572Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
      1. Yes  : GO to  R17.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  4. R4 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE 
    • Disconnect: Rear Heated Seat Module C3162B.
    • Measure the voltage between rear heated seat module C3162B-1, circuit SBB71 (WH/RD), harness side and ground.
      Fig 3: Measuring Voltage Between Rear Heated Seat Module C3162B-1, Circuit SBB71 (WH/RD), Harness Side And Ground
      G06063255Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
      1. Yes  : GO to R5.
      2. No  : VERIFY BCM fuse 71 (20A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams Information to identify the possible causes of the circuit short. TEST the system for normal operation.
  5. R5 CHECK THE HEATER CIRCUITS AND HEATER MATS FOR AN OPEN 
    • Measure the resistance between rear heated seat module C3162B-4, circuit CHS39 (GN/BU), harness side and ground.
      Fig 4: Measuring Resistance Between Rear Heated Seat Module C3162B-4, Circuit CHS39 (GN/BU), Harness Side And Ground
      G06063260Courtesy of FORD MOTOR CO.
    • Is the resistance between 2.5 and 4.5 ohms? 
      1. Yes  : GO to  R11.
      2. No  : GO to R6.
  6. R6 CHECK THE HEATER MAT GROUND CIRCUIT FOR AN OPEN 
    • Disconnect: Left Rear Backrest Heater Mat C3168.
    • Measure the resistance between left rear backrest heater mat C3168-1, circuit GD134 (BK/VT), harness side and ground.
      Fig 5: Measuring Resistance Between Left Rear Backrest Heater Mat C3168-1, Circuit GD134 (BK/VT), Harness Side And Ground
      G06458575Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
      1. Yes  : GO to R7.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  7. R7 CHECK THE HEATER CIRCUIT FOR AN OPEN OR SHORT TO GROUND 
    • Disconnect: Left Rear Cushion Heater Mat C3167.
    • Measure the resistance between:
      • rear heated seat module C3162B-4, circuit CHS39 (GN/BU), harness side and left rear cushion heater mat C3167-1, circuit CHS39 (GN/BU), harness side.
      • rear heated seat module C3162B-4, circuit CHS39 (GN/BU), harness side and ground.
        Fig 6: Measuring Resistance Between Rear Heated Seat Module C3162B-4, Circuit CHS39 (GN/BU) And Left Rear Cushion Heater Mat C3167-1, Circuit CHS39 (GN/BU)
        G06458576Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms between C3162B-4 and C3167-1, and greater than 10, 000 ohms between C3162B-4 and ground? 
      1. Yes  : GO to R8.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  8. R8 CHECK THE CUSHION HEATER MAT FOR AN OPEN 
    • Measure the resistance between left rear heated seat cushion C3167 pins 1 and 4, component side.
      Fig 7: Measuring Resistance Between Left Rear Heated Seat Cushion C3167 Pins 1 And 4, Component Side
      G06063262Courtesy of FORD MOTOR CO.
    • Is the resistance between 1.5 and 2.5 ohms? 
      1. Yes  : GO to R9.
      2. No  : INSTALL a new cushion heater mat. REFER to SEAT CUSHION HEATER MAT - REAR  . TEST the system for normal operation.
  9. R9 CHECK FOR AN OPEN OR A SHORT TO GROUND BETWEEN THE HEATER MATS 
    • Measure the resistance between:
      • left rear cushion heater mat C3167-4, circuit CHS40 (GY/VT), harness side and left rear backrest heater mat C3168-2, circuit CHS40 (GY/VT), harness side.
      • left rear cushion heater mat C3167-4, circuit CHS40 (GY/VT), harness side and ground.
        Fig 8: Measuring Resistance Between Left Rear Cushion Heater Mat C3167-4, Circuit CHS40 (GY/VT) And Left Rear Backrest Heater Mat C3168-2, Circuit CHS40 (GY/VT)
        G06458578Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms between C3167-4 and C3168-2, and greater than 10, 000 ohms between C3167-4 and ground? 
      1. Yes  : GO to R10.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  10. R10 CHECK THE BACKREST HEATER MAT FOR AN OPEN 
    • Measure the resistance between left rear backrest heater mat C3168 pins 1 and 2, component side.
      Fig 9: Measuring Resistance Between Left Rear Backrest Heater Mat C3168 Pins 1 And 2, Component Side
      G06063264Courtesy of FORD MOTOR CO.
    • Is the resistance between 1 and 2 ohms? 
      1. Yes  : The fault is intermittent. CHECK the electrical connectors for corrosion, poor pin contact or pushed out pins, particularly the pins and terminals of electrical connectors that were disconnected. Do not install any new components at this time. Components should only be installed when directed to do so in the pinpoint test  . REPAIR any intermittent wiring, terminal or connector concerns found. TEST the system for normal operation.
      2. No  : INSTALL a new backrest heater mat. REFER to SEAT BACKREST HEATER MAT - REAR  . TEST the system for normal operation.
  11. R11 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON.
    • Measure the voltage between rear heated seat module C3162A-3, circuit VHS42 (GN), harness side and ground.
      Fig 10: Measuring Voltage Between Rear Heated Seat Module C3162A-3, Circuit VHS42 (GN), Harness Side And Ground
      G06063256Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
      1. Yes  : REPAIR the circuit. GO to  R14 to check the temperature sensor for damage. If temperature sensor is OK, TEST the system for normal operation.
      2. No  : GO to R12.
  12. R12 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO GROUND 
    • Ignition OFF.
    • Measure the resistance between rear heated seat module C3162A-3, circuit VHS42 (GN), harness side and ground.
      Fig 11: Measuring Resistance Between Rear Heated Seat Module C3162A-3, Circuit VHS42 (GN), Harness Side And Ground
      G06134336Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10, 000 ohms? 
      1. Yes  : GO to R13.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  13. R13 CHECK THE TEMPERATURE SENSOR AND CIRCUITS FOR AN OPEN OR SHORT TO GROUND 
    • Connect: Left Rear Cushion Heater Mat C3167 (if previously disconnected).
    • Measure the resistance between:
      • rear heated seat module C3162A-3, circuit VHS42 (GN), harness side and C3162A-12, circuit RHS41 (GN/BN), harness side.
      • rear heated seat module C3162A-3, circuit VHS42 (GN), harness side and ground.
        Fig 12: Measuring Resistance Between Rear Heated Seat Module C3162A-3, Circuit VHS42 (GN) And C3162A-12, Circuit RHS41 (GN/BN)
        G06134337Courtesy of FORD MOTOR CO.
    • Is the resistance between 300 and 300K ohms between C3162A-3 and C3162A-12 and greater than 10, 000 ohms between C3162A-3 and ground? 
      1. Yes  : INSTALL a new heated seat module. REFER to HEATED SEAT MODULE - REAR  . TEST the system for normal operation.
      2. No  : GO to R14.
  14. R14 CHECK THE TEMPERATURE SENSOR FOR AN OPEN 
    • Disconnect: Left Rear Cushion Heater Mat C3167.
    • Measure the resistance between left rear cushion heater mat C3167 pins 2 and 3, component side.
      Fig 13: Measuring Resistance Between Left Rear Cushion Heater Mat C3167 Pins 2 And 3, Component Side
      G06063259Courtesy of FORD MOTOR CO.
    • Is the resistance between 8, 000 and 15, 000 ohms? 
      1. Yes  : REPAIR circuit RHS41 (GN/BN) or VHS42 (GN). TEST the system for normal operation.
      2. No  : INSTALL a new cushion heater mat. REFER to SEAT CUSHION HEATER MAT - REAR  . TEST the system for normal operation.
  15. R15 CHECK THE HIGH HEAT REQUEST CIRCUIT FOR AN OPEN OR SHORT TO GROUND 
    • For electrical connector access, release and lower the rear 60 percent seat backrest. Refer to the appropriate steps in HEATED SEAT MODULE - REAR  .
    • Disconnect: Left Rear Heated Seat Switch C731.
    • Measure the resistance between:
      • rear heated seat module C3162A-2, circuit CHS46 (YE/GN), harness side and left rear heated seat switch C731-1, circuit CHS46 (YE/GN), harness side.
      • rear heated seat module C3162A-2, circuit CHS46 (YE/GN), harness side and ground.
        Fig 14: Measuring Resistance Between Rear Heated Seat Module C3162A-2, Circuit CHS46 (YE/GN) And Left Rear Heated Seat Switch C731-1, Circuit CHS46 (YE/GN)
        G06458584Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms between C3162A-2 and C731-1 and greater than 10, 000 ohms between C3162A-2 and ground? 
      1. Yes  : GO to  R17.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  16. R16 CHECK THE LOW HEAT REQUEST CIRCUIT FOR AN OPEN OR SHORT TO GROUND 
    • Disconnect: Left Rear Heated Seat Switch C731.
    • For electrical connector access, release and lower the rear 60 percent seat backrest. Refer to the appropriate steps in HEATED SEAT MODULE - REAR  .
    • Measure the resistance between:
      • rear heated seat module C3162A-1, circuit CHS47 (VT/GN), harness side and left rear heated seat switch C731-5, circuit CHS47 (VT/GN), harness side.
      • rear heated seat module C3162A-1, circuit CHS47 (VT/GN), harness side and ground.
        Fig 15: Measuring Resistance Between Rear Heated Seat Module C3162A-1, Circuit CHS47 (VT/GN) And Left Rear Heated Seat Switch C731-5, Circuit CHS47 (VT/GN)
        G06458585Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms between C3162A-1 and C731-5 and greater than 10, 000 ohms between C3162A-1 and ground? 
      1. Yes  : GO to R17.
      2. No  : REPAIR the circuit. TEST the system for normal operation.
  17. R17 CHECK THE HEATED SEAT SWITCH 
    • Disconnect: Left Rear Heated Seat Switch C731.
    • Use the following chart and measure the resistance between rear heated seat switch pins, component side, while pressing the indicated switch buttons and compare the results.
      Heated Seat Switch Mode Pins Ohms
      High 1 and 6 Less than 30
      At rest 1 and 6 Greater than 10, 000
      Low 5 and 6 Less than 30
      At rest 5 and 6 Greater than 10, 000
      Fig 16: Measuring Resistance Between Rear Heated Seat Switch Pins, Component Side
      G06134341Courtesy of FORD MOTOR CO.
    • Is the heated seat switch OK? 
      1. Yes  : INSTALL a new heated seat module. REFER to HEATED SEAT MODULE - REAR  . TEST the system for normal operation.
      2. No  : INSTALL a new heated seat switch. REFER to HEATED SEAT SWITCH - REAR  .
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