Toyota prius 3rd gen stop light control relay assembly (A28)

Toyota Prius 3 ^rd Generation (XW30)

Stop Light Control Relay Assembly Wiring Guide: DIY Pinout Diagram

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What is:The Stop Light Control Relay Assembly (also called the Stop Lamp Relay or Brake Light Relay) is an electrical component in a vehicle’s lighting and braking system. It helps control the power supply to the brake lights when you press the brake pedal.

1. Introduction

      The Toyota Prius 3rd Generation Stop Light Control Relay is a key electrical component that manages the operation of the brake lights. When the brake pedal is pressed, the relay activates to supply power from the battery to the stop lamps, ensuring clear and timely illumination for safety. It works in coordination with the brake pedal switch and wiring system, protecting the circuit from overloads and ensuring reliable brake light performance during vehicle operation.

Stop Light Control Relay – Toyota Prius 3 ^rd Generation (XW30)

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1. Related parts and Accessories
   • Stop Light Switch (Brake Pedal Switch) – Detects brake pedal movement and sends the activation signal.
   • Stop Lamps (Brake Lights) – Illuminate at the rear to indicate braking.
   • Fuse (Stop Light Circuit Fuse)– Protects the stop light circuit from electrical overloads.
   • Wiring Harness and Connectors – Carry electrical current between the relay, switch, and lamps.
   • Relay Block / Junction Block – Houses and supports the stop light control relay.
   • Battery and Ground Connections – Supply and complete the electrical circuit for the stop light system.

2. Stop Light Control Relay Assembly Wiring Diagram & Pinout

A. Connector Location

• Stop Light Control Relay Assembly Position: The Stop Light Control Relay is located inside the cabin, under the dashboard, to the left of the steering column.
• Connector Type:
  • A28 (10 pin) Black housing

B. Wiring Table

Stop Light Control Relay Assembly (A28)

A28 TERMINALS OF Stop Light Control Relay Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	OUT	(G) Green	➔ A50 3 ⬌ A50 4 ➳ AR1 5 ➔ R29 8 ⬌ R29 7 ➳ VR1 15 ➔ V14 1 (STP+) [Noise Filter(Stop Light)] ➔ A50 3 ⬌ A50 4 ➳ AR1 5 ➔ R29 8 ⬌ R29 7 ➳ VR1 15 ➔ dV1 2 ➔ d1 2 (B) [Center Stop Light Assembly] ➔ A50 3 ⬌ A50 4 ➳ AR1 5 ➔ R29 8 ⬌ R28 12 ➔ R17 2 (B) [Rear Combination Light Assembly LH] ➔ A50 3 ⬌ A51 4 ➳ AS1 8 ➔ S18 2 (B) [Rear Combustion Light Assembly RH] ➔ A50 3 ⬌ A51 3 ➔ A58 6 (STP2) [Skid Control ECU with Actuator Assembly]
2	_	_	_
3	_	_	_
4	ESSI	(BE) Beige	➔ A58 21 (EXO) [Skid Control ECU with Actuator Assembly]
5	STP (Stop Light Switch)	(L) Blue	➔ A50 10 ⬌ A50 11 ➔ A26 1 [Stop Light Switch Assembly] ➔ A50 10 ⬌ A51 8 ➔ A58 33 (STP) [Skid Control ECU with Actuator Assembly] ➔ A50 10 ⬌ A51 7 ➔ A22 23 (STP) [Power Management Control ECU] ➔ A50 10 ⬌ A50 12 ➳ AL2 6 ➔ L60 1 (STP-) [Driving Support ECU Assembly]
6	+B (Battery Positive)	(R) Red	➔ 2C 12 ➤ (BAT) 10A Blade Fuse [STOP]
7	_	_	_
8	GND ( Ground )	(W-B) White/Black	➔ ▼ A1 (Ground Point)
9	ACC	(Y) Yellow	➔ A58 3 (STPO) [Skid Control ECU with Actuator Assembly]
10	_	_	_

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