Toyota prius 3rd gen Headlight Dimmer Swich Assembly (L47)

Toyota Prius 3 ^rd Generation (XW30)

Headlight Dimmer Swich Assembly Wiring Guide: DIY Pinout Diagram

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What is:The Headlight Dimmer Switch Assembly is a multifunction lever on the steering column that controls high and low beam headlights, turn signals, and sometimes fog lights. It ensures safe driving by providing reliable lighting control and signaling, connecting electrically to the vehicle’s lighting system.

Headlight Dimmer Swich Assembly – Most Common in (XW30)

Toyota OEM 84140-42070 combination light and turn signal switch

Toyota genuine replacement headlight dimmer switch (84140-42070) OEM part

Headlight Dimmer Switch lever for Toyota Prius ZVW30

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1. Introduction

The Toyota Prius 3rd generation Headlight Dimmer Switch Assembly (84140-42070) is a multifunction lever mounted on the steering column, controlling high and low beam headlights, turn signals, and sometimes fog lights. It ensures safe driving by providing reliable lighting control and signaling. This OEM component is designed for direct replacement, maintaining original functionality and fit. A faulty dimmer switch can cause headlight or indicator malfunctions, making timely replacement essential for vehicle safety and compliance with traffic regulations.

Related parts and Accessories

• Steering Column Cover – protects and houses the switch assembly.
• Combination Switch Harness – electrical connector linking the dimmer switch to the vehicle’s lighting circuits.
• Turn Signal Flasher Relay– controls the flashing of the turn indicators.
• Headlight Relay – ensures proper power supply to the headlights.
• Steering Wheel Controls (if integrated) – for multifunction levers that combine cruise or other functions.
• Mounting Screws / Clips – hardware for secure installation.

2. Headlight Dimmer Swich Assembly Wiring Diagram & Pinout

A. Connector Location

• Headlight Dimmer Swich Assembly Mounting Location: Install location left side of the steering column, behind the steering wheel.
• Connector Type:
  • L47 (20 pin) White housing

B. Wiring Table

Headlight Dimmer Swich Assembly (L47)

L47 TERMINALS OF Headlight Dimmer Swich Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	_	_	_
2	_	_	_
3	LFG (Font Fog Light Swich Common GND Pin)	(L) Blue	➔ 3A 69 ⇔ 3A 68 ➔ L47 12 (EL) [Headlight Dimmer Switch Assembly] ➔ 3A 69 ⇔ 3A 67 ➔ L93 5 ⬌ L93 3 ➔ ▼ L1 (Ground Point)
4	BFG (Font Fog Light Swich OutPut Pin)	(LG) Light Green	➔ L7 27 (FFOG) [Main Body ECU]
5	_	_	_
6	_	_	_
7	_	_	_
8	_	_	_
9	_	_	_
10	_	_	_
11	HU (Dimmer switch in high position)	(P) Pink	➔ L7 5 (HU) [Main Body ECU]
12	EL ( Turn Signal Swich and Headlight Dimmer Switch common GND Pin )	(G) Green	➔ 3A 68 ⇔ 3A 69 ➔ L47 3 (LFG) [Headlight Dimmer Switch Assembly] ➔ 3A 68 ⇔ 3A 67 ➔ L93 5 ⬌ L93 3 ➔ ▼ L1 (Ground Point)
13	TR (Right Side Turn Light OutPut Pin)	(P) Pink	➔ 3A 61 ⇔ 3B 49 ➔ 4A 7 ⇔ 4B 78 ➔ L60 34 (WNKR) [Driving Support ECU Assembly] ➔ 3A 61 ⇔ 3A 37 ➔ L55 6 (ER) [Turn Signal Flasher Assembly]
14	_	_	_
15	TL (Left Side Turn Light OutPut Pin)	(B) Black	➔ 3A 71 ⇔ 3B 60 ➔ 4A 2 ⇔ 4B 76 ➔ L60 35 (WNKL) [Driving Support ECU Assembly] ➔ 3A 71 ⇔ 3A 47 ➔ L55 5 (EL) [Turn Signal Flasher Assembly]
16	_	_	_
17	HF (Dimmer switch in high flasher position)	(LG) Light Green	➔ L7 8 (HF) [Main Body ECU]
18	T (Tail Light OutPut Pin)	(Y) Yellow	➔ L7 30 (TAIL) [Main Body ECU]
19	A (Head Light AUTO Function OutPut Pin)	(W) White	➔ L7 28 (A) [Main Body ECU]
20	H (Head Light ON OutPut Pin)	(L) Blue	➔ L7 29 (HEAD) [Main Body ECU]

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