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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 121 (Windows And Glass -- F250-F550 Super Duty) >> Diagnosis And Testing >> Glass, Frames and Mechanisms >> Pinpoint Tests >> Pinpoint Test C: The LF Power Window Is Inoperative

Pinpoint Test C: The LF Power Window 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. C1 CHECK THE DRIVER POWER WINDOW DOWN OPERATION 
    • Key in OFF position.
    • Disconnect: LF Window Control Switch C504a.
    • Connect a jumper wire between master window/door lock control switch C504a pin 8, circuit 992 (WH/BK) and ground; and between master window/door lock control switch C504a pin 7, circuit 991 (TN/LB) and positive battery terminal.
      Fig 1: Checking Driver Power Window Down Operation
      G03911558Courtesy of FORD MOTOR CO.
    • Does the driver power window go down? 

    Result / Action to Take 

    • Yes  : INSTALL a new LF window control switch. REFER to SWITCH  in this article.
    • No  : REMOVE the jumper wires. GO to C2.
  2. C2 CHECK CIRCUIT 991 (TN/LB) FOR OPEN 
    • Disconnect: LF Power Window Motor C524.
    • Measure the resistance between power window motor C524 pin 2, circuit 991 (TN/LB) harness side and master window/door lock control switch C504a pin 7, circuit 991 (TN/LB) harness side.
      Fig 2: Checking Circuit 991 (TN/LB) For Open
      G03925702Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to C3.
    • No  : REPAIR the circuit. TEST the system for normal operation.
  3. C3 CHECK THE VOLTAGE TO THE LH FRONT POWER WINDOW MOTOR - DOWN CONDITION 
    • Connect: LF Window Control Switch C504a.
    • Key in ON position.
    • Depress the DOWN position and hold on the LF window control switch.
    • Measure the voltage between LH front power window motor C524 pin 1, circuit 992 (WH/BK) harness side and ground.
      Fig 3: Checking Voltage To LH Front Power Window Motor - Down Condition
      G03911560Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : INSTALL a new left front door motor. REFER to FRONT DOOR WINDOW REGULATOR MOTOR  in this article. CLEAR the DTCs. TEST the system for normal operation.
    • No  : GO to C4.
  4. C4 CHECK THE VOLTAGE TO THE LH FRONT POWER WINDOW MOTOR - UP CONDITION 
    • Depress the UP position and hold on the LF window control switch.
    • Measure the voltage between LH front power window motor C524 pin 2, circuit 991 (TN/LB) harness side and ground.
      Fig 4: Checking Voltage To LH Front Power Window Motor - Up Condition
      G03925704Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes  : INSTALL a new left front door motor. REFER to FRONT DOOR WINDOW REGULATOR MOTOR  in this article. CLEAR the DTCs. TEST the system for normal operation.
    • No  : REPAIR the circuit. TEST the system for normal operation.
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