Toyota prius 3rd gen Seat Inner Belt Assembly (R4)(W5)

Toyota Prius 3 ^rd Generation (XW30)

Seat Inner Belt Assembly Wiring Guide: DIY Pinout Diagram

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What is:The Seat Inner Belt Assembly is a critical safety component that combines mechanical locking and electronic sensing functions to protect vehicle occupants.

1. Introduction

      The Seat Inner Belt Assembly in the Toyota Prius 3rd generation (2009–2015) is a key component of the vehicle’s seat belt and airbag safety system. It is mounted on the inner side of each front seat, next to the center console, and serves as the buckle unit where the seat belt tongue is inserted and locked.

     This assembly not only ensures the seat belt remains securely fastened during a collision but also includes a buckle switch sensor. The sensor detects whether the seat belt is latched and sends this signal to the Occupant Detection ECU (for the passenger side) or Airbag ECU (for the driver side).

Seat Inner Belt Assembly – Most Common in (XW30)

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1. Mechanical Parts component
   • Buckle Housing: – Encases the locking mechanism.
   • Latch Mechanism: – Locks the seat belt tongue securely.
   • Release Button:– Allows the belt to be unlatched.
   • Mounting Bracket: – Attaches the assembly firmly to the seat frame.
2. Electronic/Control Devices component
   • Buckle Switch (Seat Belt Switch): -Detects whether the seat belt is fastened.
   • Wiring Harness/Connector: – Connects the buckle switch to the vehicle’s Airbag ECU or Occupant Detection ECU.
   • Seat Belt Warning Indicator:– Controlled by the ECU to alert the driver/passenger if the belt is unfastened.
   • Occupant Detection ECU (for passenger side): – Uses the buckle switch signal along with seat weight sensors to determine airbag deployment conditions.

2. Seat Inner Belt Assembly Wiring Diagram & Pinout

A. Connector Location

• Seat Inner Belt Assembly Position: The Seat Inner Belt Assembly is positioned on the inner side of the seat, beside the seat cushion and next to the center console.
• Connector Type:
  • R4 (4 pin) White housing
  • W5 (2 pin) gray housing

B. Wiring Table

Seat Inner Belt Assembly Assembly (R4) (W5)

W5 TERMINALS OF Front Seat Inner Belt Assembly RH CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	1	(V) Violet	➔ R1 12 (LBE-) [Center Airbag Sensor Assembly]
2	2	(G) Green	➔ R1 11 (LBE+) [Center Airbag Sensor Assembly]
3	3	(G) Green	➔ R1 13 (LSP-) [Center Airbag Sensor Assembly]
4	4	(R) Red	➔ R1 14 (LSP+) [Center Airbag Sensor Assembly]

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W5 TERMINALS OF Front Seat Inner Belt Assembly LH CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	1	(G) Green	➔ W3 9 [Occupant Detection ECU]
2	2	(P) Pink	➔ W3 5 [Occupant Detection ECU]

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