Toyota prius 3rd gen Stop Light Switch Assembly (A26)

Toyota Prius 3 ^rd Generation (XW30)

Stop Light Switch Assembly Wiring Guide: DIY Pinout Diagram

What is: A Stop Light Switch Assembly is a brake-pedal–mounted electrical switch that activates the rear brake lights when the pedal is pressed. It also sends a brake-application signal to systems such as ABS, stability control, hybrid/EV control, and cruise control. This component ensures proper brake-light operation and supports multiple vehicle safety and control functions.

Stop Light Switch Assembly (84340-59645)

OEM Toyota stop lamp switch 84340-59645 shown with connector port.

Brake pedal–mounted stop light switch for Toyota Prius ZVW30.

Toyota Prius 3rd gen stop light switch assembly 84340-59645 close-up view.

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1. Introduction

      The  Toyota Prius 3rd Generation Stop Light Switch Assembly (84340-59645) is a key safety and control component mounted on the brake pedal bracket. It detects brake-pedal movement and immediately activates the rear brake lights while sending precise brake-status signals to the vehicle’s hybrid control system, ABS, VSC, and cruise-control module. This switch ensures accurate communication between driver actions and electronic systems, supporting safe braking response, stable vehicle control, and proper hybrid system operation. A correctly functioning stop light switch is essential for consistent brake-light illumination, reliable starting authorization, and overall system safety in the Prius 3rd generation platform.

Related parts and Accessories

• Brake-pedal pad or cover– the rubber or plastic pad on the pedal itself.
• Brake-pedal return spring – ensures the pedal comes back up properly so that the switch resets.
• Wiring harness or connector– the plug and wires linking the switch to the vehicle’s electrical system.
• Fuse or relay related to the brake-light circuit – a blown fuse or faulty relay can mimic switch failure.
• Brake light bulbs or LED units – if the switch works but lights stay off, the bulbs or light circuit may be at fault.
• Mounting bracket or pedal-shaft bushing – wear here can cause misalignment of the switch.

2. Stop Light Switch Assembly Wiring Diagram & Pinout

A. Connector Location

• Stop Light Switch Assembly Position: stop light switch is located above the brake pedal, attached to the brake pedal bracket.
• Connector Type:
  • A26 (4 pin) White housing

B. Wiring Table

Stop Light Switch Assembly (A26)

A26 TERMINALS OF Stop Light Switch Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
A26-1	1	(L) Blue	➔ A50 11 ⬌ A50 10 ➔ A28 5 (STP) [Stop Light Control Relay] ➔ A50 11 ⬌ A51 8 ➔ A58 33 (STP) [Skid Control ECU with Actuator Assembly] ➔ A50 11 ⬌ A50 7 ➔ A22 23 (STP) [Power Management Control ECU ] ➔ A50 11 ⬌ A50 12 ➔ AL2 6 ➳ L60 27 (STP-) [Driving Support ECU ]
A26-2	2	(B) Black	➔ 2C 11 ➤ (BAT) 10A Blade Fuse [STOP]
A26-3	3	(R) Red	➔ A50 5 ⬌ A51 1 ➔ A22 7 (ST1-) [Power Management Control ECU ] ➔ A50 5 ⬌ A50 6 ➔ AL2 5 ➳ L60 28 (ST1-) [Driving Support ECU ]
A26-4	4	(GR) Gray	➔ AL2 17 ➳ 3B 12 ⇔ 3B 84 ➔ 2A 32 ➤ (IG) 10A Blade Fuse [IGN]

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