The following Toyota Tacoma Wiring Diagram and Electrical Troubleshooting manual provides detail information of Tacoma’s Relay Locations (shows position of the Electronic Control Unit, Relays, Relay Block, etc), Electrical Cable Routing (describes position of Parts Connectors, Splice points, Ground points, etc.), System Circuit (electrical circuits of each system are shown from the power supply through ground points. Wiring connections and their positions are shown and classified by code according to the connection method.), Ground Points, Power Source (describes power distribution from the power supply to various electrical loads), Connector List, Part Number of the Connectors, and Overall Electrical Wiring Diagram.
In the first section of this manual you will find instruction and procedures on how to read and use the manual, also available abbreviation, wiring diagram glossary of terms and symbols.
Find the detail information about 2003 Toyota Tacoma Wiring Diagram and Electrical Troubleshooting Manual in the following page. (source: tankota.net)