Industrial / Electrical
Toyota Power Source Parts Location and Wiring Diagram
Quick reference guide for Toyota power source components, including fuse and relay locations for Junction Blocks 1, 2, and 3, along with a comprehensive electrical wiring diagram.
Table of contents
Quick guide from the manual
This document provides the technical layout for the power source system in Toyota vehicles. It identifies the physical locations of junction and relay blocks and details the electrical connections through a comprehensive wiring diagram. Use this guide to identify fuse ratings and relay functions when troubleshooting electrical issues.
Parts Location
The vehicle electrical system is organized into three main blocks:
- Junction Block No. 1: Located in the cabin, housing fuses for Engine (10A), IGN (7.5A), Tail (15A), Wiper (20A), Gauge (10A), Stop (15A), Radio (7.5A), Cigarette Lighter (15A), Turn (10A), Rear Antilock (15A), ECM-IG (20A), and Power (30A).
- Relay Block No. 2: Located in the engine bay, containing fuses for Charge (7.5A), MFI (15A), Haz-Horn (15A), Dome (15A), Headlights (10A), Gen (80A), AM1 (40A/60A), and AM2 (30A). It also houses DRL, Headlight, and Starter relays.
- Relay Block No. 3: Contains fuses for A/C (10A) and Heater (30A), along with the Heater relay.
Wiring Diagram
The wiring diagram illustrates the power distribution from the battery through the main fuse to the ignition switch and various relay-controlled circuits. It shows the path for:
- Headlight System: Includes Headlight Control Relay and Headlight Dimmer Relay (Canada specific).
- Ignition System: Connections for Engine, MFI, and ECM-IG circuits.
- Auxiliary Systems: Wiring paths for Heater, A/C, Taillight, Stop, Radio, and Wiper circuits.
Manufacturer information
Toyota Motor Corporation
Practical help
Common problems
Blown fuse in cabin
Check Junction Block No. 1. Refer to the fuse list to identify the specific circuit (e.g., Wiper 20A, Radio 7.5A) and replace with the correct amperage.
Headlight failure
Verify the Headlight Control Relay in Relay Block No. 2 and check the 10A fuses for Head (RH) and Head (LH).
Heater or A/C not working
Inspect Relay Block No. 3 for the Heater relay and the associated 10A A/C or 30A Heater fuses.
Before use
- Identify the specific block (No. 1, 2, or 3) related to the malfunctioning component.
- Verify the amperage rating of the fuse before replacement.
- Ensure the ignition is switched off before handling relays or fuses.
- Check for specific regional variations (USA vs. Canada) noted in the diagrams.
Images and diagrams
- Junction Block No. 1: Cabin-based power distribution.
- Relay Block No. 2: Engine bay power distribution including main battery feed.
- Relay Block No. 3: Dedicated heater and A/C power management.
Model compatibility
- Some components are region-specific, particularly Headlight relays and DRL systems for Canada.
- Power Door Lock and Power Window features affect the Power (30A) fuse configuration in Junction Block No. 1.
Manual page author
Emily Carter
User documentation editor
Prepares concise manual descriptions and highlights the most useful setup, operation, and maintenance information for readers.