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Overhead Junction Block: Inspection

  1. INSPECT OVERHEAD JUNCTION BLOCK ASSEMBLY 

    Disconnect the connector from the overhead J/B and inspect the connector on the wire harness side, as shown.

    Fig 1: Identifying Overhead Junction Block Assembly Connector Terminals
    G03377164Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR TERMINALS SPECIFIED CONDITION

    Tester connection Condition Specified condition
    1 - Ground Constant Continuity
    5 - Ground Constant Continuity
    13 - Ground Constant Battery positive voltage
    17 - Ground Constant Battery positive voltage
    26 - Ground Ignition switch OFF or ACC No voltage
    Ignition switch ON Battery positive voltage

    If continuity is not as specified, replace the overhead junction block.

  2. Overhead J/B side: INSPECT OVERHEAD JUNCTION BLOCK ASSEMBLY 
    Fig 2: Overhead Junction Block Assembly Connector Terminals - Overhead J/B Side
    G03377165Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR TERMINALS SPECIFIED CONDITION

    Circuit name Tester connection Specified condition
    Power source circuit A12-A26-A27-A28 Continuity
    Power source circuit A13-C6-D6 Continuity
    Multiplex communication circuit A14-A30-A31 Continuity
    Ground circuit A1-A15-A16-A32-C8-D2-E4-Body ground Continuity
    Microphone circuit B1-A19 Continuity
    Microphone circuit B4-A2 Continuity
    Microphone circuit B5-A3 Continuity
    Microphone circuit B6-A18 Continuity
    Mayday switch circuit D1-A23 Continuity
    Mayday switch circuit D3-A22 Continuity
    Mayday switch circuit D5-A21 Continuity
    Rader sensor circuit E1-A7 Continuity
    Rader sensor circuit E2-A8 Continuity
    Rader sensor circuit E3-A9 Continuity

    If continuity is not as specified, replace the overhead J/B assembly.