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+B Power Source Circuit Test

NOTE: Use this procedure to check for problems in circuit between driver's seat ECU and DOOR fuse.
  1. Check DOOR (30-amp) fuse, located in junction block No. 1. If DOOR fuse is open, repair short to ground in Blue/White wire between DOOR fuse and driver's seat ECU, or between driver's seat ECU and seat motors. See WIRING DIAGRAMS . If DOOR fuse is okay, go to next step.
  2. Ensure ignition is off. At driver's seat, remove bolts for front vertical adjuster. Lift front end of seat slightly for access to driver's seat ECU (do not lift too far; harness clamp may come loose). Remove driver's seat ECU, leaving wiring harness connectors attached.
  3. At connector "A" of driver's seat ECU, connect voltmeter negative lead (backprobe) to terminal No. 1 (White/Black wire), and connect positive lead to terminals No. 5 and 14 (Blue/White wires). See Fig 1. If battery voltage is present, return to TROUBLE SHOOTING .
  4. If battery voltage is not present, measure resistance between terminal No. 1 and ground. If resistance is one ohm or more, repair open on White/Black wire ground circuit. See WIRING DIAGRAMS . If resistance is less than one ohm, repair open on Blue/White wires between battery and driver's seat ECU.
Fig 1: Identifying Drivers Seat ECU Harness Connector Terminals (Harness Side View)
G94F47568Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002