2018 Subaru Crosstrek Fuse Box Diagram & Amperages

As an ASE-certified master technician, I regularly see drivers struggling to locate and identify fuses when an electrical component goes down. Whether your 12V accessory port stopped working or your headlights went dark, checking the fuses is always the first diagnostic step.

Below is a comprehensive guide to the fuse box locations, diagrams, and amperage ratings for the 2018 Subaru Crosstrek.

Note: Fuse configurations can vary slightly depending on your specific trim level (Base, Premium, Limited) and optional equipment. Always verify the fuse layout using the printed legend on the inside of your fuse box lid before pulling or replacing fuses.

Quick Answer: Fuse Box Locations

The 2018 Subaru Crosstrek features two main fuse boxes:

1. Under-Hood Fuse Box (Engine Compartment): Located on the driver's side of the engine bay, near the battery. It houses high-amperage fuses, relays, and critical engine management circuits.
2. Passenger Compartment Fuse Box (Dash/Kick-Panel): Located inside the cabin on the driver's side. You will need to remove the small coin tray/storage cubby to access it. Pull the cubby outward and unhinge it to reveal the fuses.

(Note: The 2018 Subaru Crosstrek does not have a separate rear trunk or cargo area fuse box.)

Under-Hood Fuse Box (Engine Compartment)

This fuse box manages the heavy-duty electrical loads and critical powertrain components. Below is a diagram of the most common circuits.

Common Relays in the Under-Hood Box:

• Starter Relay: Engages the starter motor.
• A/C Relay: Controls the air conditioning compressor clutch.
• Main Engine Relay (FI): Powers the ECM and fuel injection system.
• Fuel Pump Relay: Typically located here or adjacent to the passenger kick-panel, depending on emissions equipment.

Passenger Compartment Fuse Box (Dash/Instrument Panel)

This fuse box controls the majority of the interior electronics, lighting, and cabin accessories.

(Note on Trailer Brakes: The 2018 Crosstrek is not pre-wired for a heavy-duty trailer brake controller like an HD truck, though aftermarket 4-pin lighting harnesses usually tie into the tail light circuits or directly to the battery with an inline fuse).

How to Test a Fuse

Before throwing parts at an electrical problem, you should always test the fuses. There are two primary ways to do this:

1. Visual Inspection: Using the plastic fuse puller (usually stored in the under-hood fuse box lid), pull the suspect fuse. Look at the metal wire inside the plastic housing. If the metal bridge is broken, burnt, or melted, the fuse has blown and needs to be replaced. Always replace it with a fuse of the exact same amperage and color.
2. Multimeter or Test Light (Preferred Method): You don't even need to pull the fuse for this. Turn the ignition to the "ON" position (without starting the engine). Take a 12V test light or a multimeter grounded to the chassis. Touch the probe to the two small metal testing tabs exposed on the top of the fuse.
   • If the test light illuminates (or the multimeter reads ~12V) on both sides, the fuse is good.
   • If it only lights up on one side, the fuse is blown.
   • If neither side lights up, the circuit is not currently receiving power (the switch for that component may be off, or a relay is un-energized).

Common Blown Fuses on the 2018 Subaru Crosstrek

As a technician, I see certain fuses blow far more frequently than others on the Crosstrek platform:

• 12V Power Outlets (Fuses #9 & #10 in the Dash): This is the number one fuse failure. Dropping a coin in the socket, using a cheap/faulty phone charger, or plugging in a high-draw tire inflator will instantly pop these 20-amp fuses. If your phone isn't charging, check these first.
• Headlight Fuses (Fuses #7-10 Under-Hood): When an incandescent or halogen bulb burns out, the filament can sometimes short across the internal supports, popping the respective low or high beam fuse. If a new bulb doesn't fix your headlight, check the under-hood fuse box.
• Tail / Parking Lights (Fuse #5 in the Dash): Often blown when owners attempt to install aftermarket LED bulbs or if a trailer wiring harness develops a short due to road salt and corrosion.

Always remember: a fuse blows to protect the wiring harness from melting and catching fire. If you replace a blown fuse and it immediately pops again, do not install a higher amperage fuse. You have a dead short in the system that requires professional diagnosis.

Find a trusted shop on Repairius.