Where is the fuse box on a 2012 Lexus IS 350?
The fuse boxes on a 2012 Lexus IS 350 are located in three places: the engine bay, inside the cabin, and in the rear trunk area.
Understanding where these boxes live helps you diagnose blown fuses or replace a faulty relay without guesswork. Each box has a cover with a fuse map, and the layout is also described in the owner’s manual.
Fuse box locations
The following sections identify the three primary fuse locations and how to access them on the 2012 IS 350.
Engine compartment fuse box
The engine bay houses a dedicated fuse/relay box located on the passenger side of the engine compartment, near the firewall. It is a black plastic container with a removable cover labeled FUSE/RELAY. To access it, pull off the cover and use the built‑in fuse puller (or a suitable fuse extractor) to remove or inspect fuses. The lid’s underside typically shows a diagram of which fuses power major components such as engine management, fuel system, and electronics.
Consult the diagram on the inside of the cover for exact fuse numbers and circuits. If you’re replacing a blown fuse, ensure the replacement matches the amperage rating printed on the fuse or in the diagram.
Interior (cabin) fuse box
The interior fuse box is situated inside the cabin, commonly behind a panel on the driver’s side knee area under the dash. Access is gained by removing the panel or cover, which reveals the fuses arranged in a tray. A card or sticker inside the cover shows the fuse assignments for dashboards, lighting, climate control, audio, and other interior systems.
When replacing a fuse here, start with the most frequently used interior circuits if you’re troubleshooting a specific symptom, and always replace with the recommended amperage to avoid electrical issues.
Trunk (rear) fuse box
A third fuse box is located in the trunk/ rear compartment, typically on the left or right side panel behind a small removable cover. This box protects rear electrical components such as tail lights, trunk features, and related relays. Remove the panel to access the fuses; the diagram on the inside of the cover shows the circuit assignments.
If you’re working in the trunk, ensure the ignition is off and disconnect the battery if you’ll be replacing power‑related components that require it, following the manual’s safety guidelines.
Summary
The 2012 Lexus IS 350 uses three fuse boxes: in the engine compartment, inside the cabin, and in the trunk. Each box has a removable cover with a fuse map to guide you to the correct fuse for a given circuit. Always refer to the diagrams on the covers or in the owner’s manual to confirm fuse numbers and amperage before replacing anything.
