Check the passenger compartment panel first if interior electronics or dashboard systems stop working, since most low-amperage circuits are located there. This panel is usually behind a trim cover on the passenger side and contains slots rated from 5A to 30A for lighting, infotainment, and control modules.
The engine compartment distribution unit near the battery handles high-current protection for systems such as starter motor, cooling fans, and charging system. These larger cartridge-style components often range from 30A to over 100A and are grouped separately for direct power routing.
Match each electrical issue to a specific circuit before removing anything. For example, power seat or window failure often relates to a 20A or 30A slot inside the cabin, while cooling fan or charging issues point to high-amperage positions under the hood. Use the printed layout on each cover to identify slots accurately.
Remove each component with a puller tool and inspect the internal metal strip. A broken or burned link confirms failure. Replace only with the same amperage rating to prevent overheating, wiring damage, or malfunction in connected systems.
2015 Ford F150 XLT Fuse Box Diagram with Locations and Circuit Details
Check the power distribution module in the engine compartment near the battery and the interior panel on the passenger side kick area to match each slot with its assigned circuit before replacing any element. Use the lid legend or service manual to verify amperage ratings such as 10A for lighting control, 20A for power outlets, and 30A or higher for blower motor and trailer circuits.
The engine compartment unit contains high-current links and relays for starter, cooling fan, ABS pump, and charging system, while the cabin panel handles accessories like radio, interior lighting, door locks, and diagnostic connector. Each position is numbered; for example, lower rows often carry accessory circuits, while upper rows route ignition and control modules. Misplacing a component with incorrect rating can lead to wiring damage or intermittent faults, so confirm slot numbering, label orientation, and relay grouping before installation. Cross-check circuit names such as PCM power, fuel pump relay, and trailer tow feed to avoid confusion between similar amperage positions.
Use a test light or multimeter to confirm voltage at both sides of each installed element, inspect for corrosion on terminals, and ensure relays click when energized; this approach helps isolate issues tied to lighting, HVAC, or ignition feed without unnecessary part swaps.
Passenger compartment fuse panel layout and slot function mapping
Locate the interior power panel behind the right-side kick trim and match each numbered slot with the legend printed on the cover to confirm circuit purpose before pulling any component.
The upper row typically carries ignition-switched circuits such as instrument cluster, steering column controls, and airbag module, while the middle section feeds audio unit, climate control, and central locking; lower positions often supply constant battery lines for interior lamps and diagnostic connector.
Use amperage markings to distinguish roles: 5A–10A slots are linked to control modules and sensors, 15A–20A positions power accessories like infotainment and 12V outlets, and higher ratings handle seat adjustment or rear defrost relay triggers.
Check slot numbering orientation carefully since reversed viewing angles can lead to installing a component in the wrong position, especially when accessing the panel from below.
When tracing a fault, probe both terminals of each installed element with a multimeter; voltage on only one side indicates a blown link, while no voltage suggests upstream relay or wiring interruption.
Look for grouped circuits sharing a common relay feed; for example, power windows and door locks often depend on a single control relay located adjacent to the panel, so a failure there can affect multiple slots at once.
Clean any oxidized contacts, ensure tight seating, and avoid mixing different ratings within adjacent positions to prevent overheating or unintended shutdown of connected systems.