2024 Ford F-350 Super Duty – Fuse Box Diagram & Amperage

Quick answer

The 2024 Ford F-350 Super Duty typically has three main fuse box locations: the Power Distribution Box (under-hood), the Smart Junction Box (SJB) located behind the passenger kick panel, and the Battery Junction Box (BJB) often found in the engine compartment near the battery. Some configurations, especially those with optional accessories or upfitter switches, may have additional auxiliary fuse panels.

Power Distribution Box (Under-hood)

This fuse box is located in the engine compartment, usually on the driver's side near the battery. It houses many of the fuses and relays for critical engine functions, lights, and high-current accessories.

Relay Locations (Under-hood Power Distribution Box):

• R1: Fuel Pump Relay
• R2: Starter Relay
• R3: Horn Relay
• R4: A/C Clutch Relay
• R5: High Beam Headlight Relay
• R6: Blower Motor Relay

Smart Junction Box (SJB) / Passenger Kick Panel Fuse Box

This fuse box is located behind the passenger kick panel, often requiring the removal of a trim piece for access. It manages many of the interior electrical components and accessories.

Relays (SJB): While most circuits in the SJB are fused, some interior functions might use integrated relays or micro-relays that are not user-serviceable without replacing the entire SJB. Consult your owner's manual for specific relay identification within the cabin.

Battery Junction Box (BJB)

Typically located in the engine compartment, often adjacent to or integrated with the positive battery terminal. This box often contains maxi-fuses and circuit breakers for high-current loads and provides direct battery power to major systems.

Relays (BJB): High-current relays such as the glow plug relay (on diesel models) or main power relays might be located within or near the Battery Junction Box.

How to test a fuse

Testing a fuse is a straightforward process:

1. Safety First: Ensure the vehicle is off and the key is removed from the ignition. For the under-hood and battery junction boxes, it's wise to disconnect the negative battery terminal if you're uncomfortable working near live circuits.
2. Locate the Fuse: Refer to your owner's manual or the diagrams above and on the fuse box lid to identify the suspicious fuse.
3. Visual Inspection: Many fuses have a visible wire inside. If this wire is broken or melted, the fuse is blown and needs replacement.
4. Use a Fuse Tester or Multimeter: For a more definitive test, especially for fuses where the wire isn't easily visible, use a fuse tester or a multimeter set to the continuity setting.
   • Fuse Tester: Simply touch the probes of the tester to the two small metal test points on the top of the fuse. If the light on the tester illuminates, the fuse is good. If not, it's blown.
   • Multimeter: Remove the fuse from its slot. Touch one probe to each metal terminal of the fuse. If the multimeter beeps or shows a reading of