Where is the fuse on the 2017 F350 trailer light?
The fuse for trailer lights on a 2017 Ford F-350 is usually in the engine-compartment power distribution box, labeled TRLR or Trailer Tow. If not found there, check the interior fuse panel and refer to the diagram on the fuse box lid for the exact fuse number and rating.
Where the trailer light fuse is typically found
Use these checks to locate the correct fuse that protects the trailer-light circuit. The exact location can vary based on trim level, optional equipment, and production changes, so always verify with the box label or owner's manual.
Under-hood Power Distribution Box
Start with the main power hub under the hood. This is the most common place for the trailer-light fuse on many F-Series trucks.
- Open the hood and locate the Power Distribution Box in the engine bay (often near the battery or along the inner fender).
- Remove the cover and read the diagram printed on the underside or inside the lid; look for fuses labeled TRLR, TRLR TOW, Trailer Tow, or similar wording.
- Pull the identified fuse out and inspect it; a blown fuse will typically have a broken filament or a melted appearance.
- If blown, replace with a fuse of the same amperage rating as indicated by the diagram (common trailer-circuit ratings are 15A, 20A, or 30A, depending on the circuit).
- Reinstall the fuse securely, reconnect the battery if disconnected, and test the trailer lights with the trailer connected.
Conclusion: The under-hood box is the primary location many owners check first for the trailer-light fuse, but not all configurations place the TRLR fuse here. Always confirm with the lid diagram for your exact build.
Interior Fuse Panel
If the under-hood fuse box doesn’t show a TRLR label or if your vehicle uses a different configuration, the trailer-light fuse may reside in the interior fuse panel.
- Locate the interior fuse panel, typically behind the glove box or under the dash on the driver’s side.
- Consult the fuse diagram on the panel or in the owner's manual to identify any fuse labeled TRLR, Trailer Tow, or an equivalent designation for trailer lighting.
- Remove and inspect the identified fuse; if blown, replace with the correct amperage as indicated by the diagram.
- After replacement, test the trailer lights again with the trailer connected.
Conclusion: The interior panel serves as a backup or alternative protection point for trailer lighting depending on trim level and optional equipment.
Verification steps and troubleshooting tips
Even with a good fuse, trailer lights can fail due to grounds, wiring, or module issues. Consider these checks if replacement doesn’t restore function.
- Ensure a solid ground between the trailer and the tow vehicle; a bad ground is a common cause of dim or nonfunctional lights.
- Inspect the trailer wiring harness and connectors for corrosion, damaged insulation, or bent pins; clean or replace as needed.
- Test the trailer lights with a known-good trailer or a diagnostic tester to determine whether the issue is in the truck or the trailer.
- If the problem persists, consider the Integrated Trailer Relay Controller (ITRC/ITBC) or other tow-relay modules as potential culprits and have them diagnosed by a dealer or qualified technician.
In short, fuse location is a key first step, but electrical problems can involve multiple components beyond the fuse itself.
Summary
For a 2017 F-350, start by checking the engine-compartment Power Distribution Box for a TRLR, TRLR TOW, or Trailer Tow fuse, using the lid diagram to identify the exact fuse and amperage. If it isn’t there, inspect the interior fuse panel behind the glove box or under the dash. Always replace a blown fuse with the correct amperage and verify grounds and trailer wiring. If issues persist, consult a Ford dealer or a qualified technician to inspect trailer wiring and any tow-relay modules.
