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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 197 (Seat System -- F250-F550 Super Duty) >> Diagnosis And Testing >> Seats >> Pinpoint Tests >> Pinpoint Test G: The Heated Seat Is Inoperative

Pinpoint Test G: The Heated Seat Is Inoperative

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

Test Step 

  1. G1 CHECK HEATED SEAT SWITCH OPERATION 
    • Key in ON position.
    • Press the heated seat switch on the driver and passenger seats
    • Do both heated switch indicators illuminate? 

    Result / Action to Take 

    • Yes  : If both indicators illuminate, GO to PINPOINT TEST H .

      If only one indicator illuminates, GO to  G5.

    • No  : GO to G2.
  2. G2 CHECK THE HEATED SEAT RELAY CIRCUITS 
    • Key in OFF position.
    • Disconnect: Heated Seat Relay (C3250) (located under the driver seat).
    • Key in ON position.
    • Measure the voltage at heated seat relay C359 pin 85, circuit 295 (LB/PK), harness side and ground; and between C359 pin 30, circuit 1153 (RD/BK), harness side and ground.
      Fig 1: Checking Heated Seat Relay Circuits
      G03911387Courtesy of FORD MOTOR CO.
    • Are the voltages greater than 10 volts? 
    • Yes  : GO to G3.
    • No  : REPAIR circuit 295 (LB/PK) or 1153 (RD/BK). TEST the system for normal operation.
  3. G3 CHECK HEATED SEAT RELAY GROUND CIRCUIT 
    • Key in OFF position.
    • Measure the resistance between heated seat relay C359 pin 86, circuit 57 (BK), harness side and ground.
      Fig 2: Checking Heated Seat Relay Ground Circuit
      G03911388Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to G4.
    • No  : REPAIR circuit 57 (BK). TEST the system for normal operation.
  4. G4 CHECK THE HEATED SEAT RELAY 
    • Install a fused jumper lead between heat seat relay C359 pin 30, circuit 1153 (RD/BK), harness side and C359 pin 87, circuit 1255 (WH/RD) harness side.
      Fig 3: Checking Heated Seat Relay
      G03903236Courtesy of FORD MOTOR CO.
    • Do both heated seat indicators illuminate when pressed? 
    • Yes  : INSTALL a new heated seat relay. TEST the system for normal operation.
    • No  : REPAIR circuit 1064 (YE/BU) to switches. TEST the system for normal operation.
  5. G5 CHECK INOPERATIVE HEATED SEAT SWITCH INPUT 
    • Key in OFF position.
    • Disconnect: Heated Seat Switch C320 (Driver) or C321 (Passenger) For the inoperative heated seat.
    • Key in ON position.
    • Measure the voltage between driver heated seat switch C320 (passenger C321) pin 2, circuit 1255 (WH/RD), harness side and ground.
      Fig 4: Checking Inoperative Heated Seat Switch Input
      G03903237Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : GO to G6.
    • No  : REPAIR circuit 1255 (WH/RD). TEST the system for normal operation.
  6. G6 CHECK CIRCUIT 57 (BK) FOR AN OPEN 
    • Measure the resistance between heated seat switch C320 (passenger C321) pin 4, circuit 57 (BK), harness side and ground.
      Fig 5: Checking Circuit 57 (BK) For Open
      G03903238Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : INSTALL a new heated seat switch. TEST the system for normal operation.
    • No  : REPAIR circuit 57 (BK). TEST the system for normal operation.
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