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Section 788 (Power Seat Control System): Inspection

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT DRIVER'S POWER SEAT SWITCH CIRCUIT (See  POWER SEAT CONTROL SWITCH CIRCUIT  ) 
  2. INSPECT PASSENGER'S POWER SEAT SWITCH CONTINUITY 

    Slide switch: 

    SLIDE SWITCH

    Switch position Tester connection Specified condition
    FRONT 4-7-(6) 8-11-(12) Continuity
    OFF 4-7-(6)-8 Continuity
    BACK 4-11-(12) (6)-7-8 Continuity

    Front vertical switch: 

    FRONT VERTICAL SWITCH

    Switch position Tester connection Specified condition
    UP (6)-7-10 9-11-(12) Continuity
    OFF (6)-7-9-10 Continuity
    DOWN 6-(7)-9 10-11 - (12) Continuity

    Lifter switch: 

    LIFTER SWITCH

    Switch position Tester connection Specified condition
    UP 2-(6)-7 3-11-(12) Continuity
    OFF 2-3-(6)-7 Continuity
    DOWN 2-11-(12) 3-(6)-7 Continuity

    Reclining switch: 

    RECLINING SWITCH

    Switch position Tester connection Specified condition
    FORWARD 1-11-(12) 5-(6)-7 Continuity
    OFF 1 - 5 - (6) - 7 Continuity
    REAR 1-(6)-7 5-11-(12) Continuity

    If continuity is not as specified, replace the switch.

    Fig 1: Inspecting Passenger's Power Seat Switch Continuity
    G03375607Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. INSPECT PASSENGER'S POWER SEAT SWITCH CIRCUIT 
    1. Disconnect the switch connector and connect the seat wire harness to the floor wire harness.
    2. Inspect the connector on the wire harness side.
    Fig 2: Inspecting Connector On Wire Harness Side
    G03375608Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    SPECIFIED CONDITION

    Tester connection Condition Specified condition
    7 - Ground Always Continuity
    11 -Ground Always Battery positive voltage

    If circuit is not as specified, inspect the circuits connected to other parts.

  4. INSPECT DRIVER'S LUMBAR SUPPORT SWITCH CONTINUITY 
    SPECIFIED CONDITION

    Switch position Tester connection Specified condition
    FORWARD 1-4
    2-3    		 Continuity
    OFF 1-2-3 Continuity
    RELEASE 1-3
    2-4    		 Continuity

    If continuity is not as specified, replace the switch.

    Fig 3: Inspecting Driver's Lumbar Support Switch Continuity
    G03375609Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. INSPECT DRIVER'S LUMBAR SUPPORT SWITCH CIRCUIT 
    1. Disconnect the switch connector and connect the seat wire harness to the floor wire harness.
    2. Inspect the connector on the wire harness side.
    Fig 4: Inspecting Connector On Wire Harness Side
    G03375610Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    SPECIFIED CONDITION

    Tester connection Condition Specified condition
    3 - Ground Always Continuity
    4 - Ground Always Battery positive voltage

    If circuit is not as specified, inspect the circuits connected to other parts.

  6. INSPECT SLIDE MOTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, check that the motor turns clockwise.
    2. Reverse the polarity, and check that the motor turns counterclockwise.

    If operation is not as specified, replace the seat adjuster.

    Fig 5: Inspecting Slide Motor Operation
    G03375611Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. INSPECT SLIDE MOTOR PTC THERMISTOR OPERATION 

    (): Passenger side 

    1. Connect the battery positive (+) lead to terminal 2(1), the ammeter positive (+) lead to terminal 1 (2) and the ammeter negative (-) lead to the battery negative (-) terminal, then move the seat cushion to the front position.
    2. Continue to apply voltage, and check that current changes to less than 1 ampere within 4 to 90 seconds.
      Fig 6: Connecting Battery Positive (+) Lead To Terminal 2
      G03375612Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the leads from terminals.
    4. Approximately 60 seconds later, connect the battery positive (+) lead to terminal 1 (2) and the battery negative (-) lead to terminal 2 (1), and check that the seat cushion begins to move backwards.

    If operation is not as specified, replace the seat adjuster.

    Fig 7: Locating Seat Cushion Begins To Move Backwards
    G03375613Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  8. INSPECT FRONT VERTICAL MOTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, and check that the motor turns clockwise.
    2. Reverse the polarity, and check that the motor turns counterclockwise.

    If operation is not as specified, replace the seat adjuster.

    Fig 8: Checking Motor Turns Clockwise
    G03375614Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  9. INSPECT FRONT VERTICAL MOTOR PTC THERMISTOR OPERATION 

    (): Passenger side 

    1. Connect the battery positive (+) lead to terminal 1 (2), the ammeter positive (+) lead to terminal 2 (1) and the ammeter negative (-) lead to the battery negative (-) terminal, then move the seat cushion to the highest position.
    2. Continue to apply voltage, and check that the current changes to less than 1 ampere within 4 to 90 seconds.
      Fig 9: Locating Seat Cushion To Highest Position
      G03375615Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the leads from the terminals.
    4. Approximately 60 seconds later, connect the battery positive (+) lead to terminal 2 (1) and the battery negative (-) lead to terminal 1 (2), and check that the seat cushion begins to descend.

    If operation is not as specified, replace the seat adjuster.

    Fig 10: Locating Seat Cushion Begins To Descend
    G03375616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  10. INSPECT LIFTER MOTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, and check that the motor turns clockwise.
    2. Reverse the polarity, and check that the motor turns counterclockwise.

    If operation is not as specified, replace the seat adjuster.

    Fig 11: Identifying Motor Turns Clockwise
    G03375617Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  11. INSPECT LIFTER MOTOR PTC THERMISTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 (2), the ammeter positive (+) lead to terminal 2 (1) and the ammeter negative (-) lead to the battery negative (-) terminal, then move the seat to the highest position.
    2. Continue to apply voltage, and check that the current changes to less than 1 ampere within 4 to 90 seconds.
      Fig 12: Locating Seat To Highest Position
      G03375618Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the leads from the terminals.
    4. Approximately 60 seconds later, connect the battery positive (+) lead to terminal 2 (1) and the battery negative (-) lead to terminal 1 (2), and check that the seat begins to descend.

    If operation is not as specified, replace the seat adjuster.

    Fig 13: Locating Seat Begins To Descend
    G03375619Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  12. INSPECT RECLINING MOTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, and check that the motor turns clockwise.
    2. Reverse the polarity, and check that the motor turns counterclockwise.

    If operation is not as specified, replace the seat adjuster.

    Fig 14: Identifying Motor Turns Counterclockwise
    G03375620Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  13. INSPECT RECLINING MOTOR PTC THERMISTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 2, the ammeter positive (+) lead to terminal 1 and the ammeter negative (-) lead to the battery negative (-) terminal, then recline the seat back to the most forward position.
    2. Continue to apply voltage, and check that the current changes to less than 1 ampere within 4 to 90 seconds.
      Fig 15: Locating Recline Seat Back To Most Forward Position
      G03375621Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the leads from the terminals.
    4. Approximately 60 seconds later, connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, and check that the seat back begins to fall backward.

    If operation is not as specified, replace the seat adjuster.

    Fig 16: Locating Seat Back Begins To Fall Backward
    G03375622Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  14. INSPECT LUMBAR SUPPORT MOTOR OPERATION 
    1. Connect the battery positive (+) lead to terminal 1 and the battery negative (-) lead to terminal 2, and check that the lumbar support moves to release side.
      Fig 17: Locating Lumbar Support Moves To Release Side
      G03375623Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Reverse the polarity, check that the lumbar support moves forward.

    if operation is not as specified, replace the seat adjuster.

    Fig 18: Locating Lumbar Support Moves Forward
    G03375624Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  15. INSPECT LUMBAR SUPPORT MOTOR CIRCUIT BREAKER OPERATION
    1. Connect the battery positive (+) lead to terminal 2 and the battery negative (-) lead to terminal 1 on the lumbar support motor connector and move the lumbar support to front end position.
      Fig 19: Locating Lumbar Support To Front End Position
      G03375625Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Continue to apply voltage, and check that a circuit breaker operation noise can be heard within 4 to 60 seconds.
    3. Reverse the polarity, check that the lumbar support begins to move to the release side within approximately 60 seconds.

    If operation is not as specified, replace the motor.

    Fig 20: Locating Lumbar Support Begins To Move To Release Side
    G03375626Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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