Check the power distribution panel layout before replacing any blown element, as incorrect identification can disable working systems or cause repeated failures. Use the factory labeling inside the cover and match it with the circuit chart to confirm amperage ratings and component roles.
The chassis uses multiple electrical panels, typically placed under the dashboard and within the engine compartment. Each unit contains blade-type links and switching components that control lighting, ignition, HVAC, and auxiliary equipment. Always verify the amperage value printed on each slot before installing a replacement, since using a higher rating may damage wiring.
For troubleshooting, inspect both the cabin and engine-side panels, as related systems are often split across different sections. For example, a non-working blower motor may be tied to one panel, while its relay sits in another. This separation requires checking both locations to isolate the fault accurately.
Corrosion, loose contacts, and heat marks are common signs of failure in these assemblies. Clean terminals and ensure tight seating during inspection, as poor contact can mimic a blown link. Keeping a printed circuit map in the vehicle speeds up diagnosis and reduces guesswork during roadside checks.
2020 Ford F59 Fuse Box Diagram With Relay Locations and Circuit Details
Locate both power distribution units before diagnosing any electrical issue, as circuits are divided between the cabin panel and the engine compartment module. Access the interior unit beneath the dashboard on the driver side, while the under-hood unit sits near the battery and contains high-current links for major systems.
Match each slot number with its assigned circuit using the cover label or service manual chart. Typical assignments include ignition coils, fuel pump control, brake lights, and HVAC components. Ratings usually range from 5A for control circuits to 40A or higher for motors and heavy loads, and installing the wrong rating may lead to wiring damage or repeated failure.
Relay positions and functions
Switching modules are grouped alongside the blade elements, often in the same enclosure. These components handle load switching for systems like starter operation, cooling fans, and air conditioning compressors. Identify each relay by its position code, then verify operation by swapping with a matching unit from a non-critical circuit or using a multimeter to check continuity.
Circuit tracing and fault isolation
Follow the wiring path from the affected component back to its assigned slot and switching unit. For example, if headlights fail, inspect both the lighting circuit link and the corresponding relay in the engine-side panel. Voltage testing at the input and output terminals helps determine whether the issue lies in the protection element, the switch module, or the wiring itself.
Inspect for heat discoloration, melted plastic, or loose terminals during every check. Secure each component firmly and clean контакts if oxidation appears, since poor connections can interrupt current flow without visible damage to the protective element.
Exact location of fuse boxes in 2020 Ford F59 chassis and how to access them
Open the driver-side lower dash panel first, as the primary interior electrical center is mounted behind it. Remove the trim cover by pulling it straight out or releasing retaining clips, then identify the panel fixed near the steering column support bracket.
The engine compartment power unit sits close to the battery on the left side of the bay. Release the plastic cover by pressing the locking tabs and lift it upward to expose high-current links and switching components used for cooling fans, starter control, and charging circuits.
Use a flashlight to inspect tight areas, since wiring harnesses and brackets can partially block visibility. In some configurations, access from above is limited, so reaching from the side of the engine bay provides a clearer view of slot labels and component layout.
For step vans and stripped chassis builds, an additional panel may be installed by the body manufacturer, often under the passenger seat or inside a side compartment. Check aftermarket wiring carefully, as added circuits may not match factory markings and can lead to confusion during diagnostics.
Before removing any component, disconnect the negative battery terminal to prevent short circuits. After inspection or replacement, ensure each element is fully seated and the protective cover is secured tightly to keep moisture and debris out.