Section 54 (Overhead Junction Block): Inspection

WARNING: This page is about a different car, the 2005 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

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 Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Overhead Junction Block Connector Terminal Legend
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If continuity is not as specified, repair or replace the wire harness.

Overhead J/B side:

INSPECT OVERHEAD JUNCTION BLOCK ASSEMBLY

Fig 3: Identifying Overhead Junction Block Connector Terminals - Over Head J/B Side

TESTER CONNECTION SPECIFIED CONDITION

Circuit name	Tester connection	Specified condition
Power source circuit	A8-B6-E6	Continuity
Power source circuit	A11-B8-G1	Continuity
Ground circuit	A1-B2-E8-D3-F1	Continuity
Microphone circuit	A2-B10-G4	Continuity
Microphone circuit	A3-B9-G2	Continuity
Mayday switch circuit	A13-B7-F4	Continuity
Mayday switch circuit	A7-B4-F3	Continuity
Mayday switch circuit	A14-B3-F12	Continuity

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