2018 International LT Fuse Box Diagram & Amperage
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Quick answer
On the 2018 International LT, you will find two primary fuse box locations:
- Under-Hood Fuse Box (Power Distribution Center): Located near the driver's side of the engine compartment.
- In-Cab Fuse Box: Located in the driver's side dash, accessible by removing the kick panel near the pedals.
This vehicle does not have a fuse box in the trunk or cargo area.
Under-Hood Fuse Box / Power Distribution Center
This fuse box contains high-amperage fuses and relays that control major vehicle systems. The layout can vary slightly based on optional equipment, but this table covers the most common configuration. Always check the diagram on the inside of your fuse box lid to confirm fuse locations and ratings.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 60A | Yellow | Trailer Power |
| F2 | 30A | Green | ABS Pump |
| F3 | 40A | Green | Blower Motor (HVAC) |
| F4 | 20A | Yellow | Engine Control Module (ECM) - Battery |
| F5 | 15A | Blue | Fuel Heater |
| F6 | 30A | Green | Ignition Switch |
| F7 | 20A | Yellow | Headlights - High Beams |
| F8 | 20A | Yellow | Headlights - Low Beams |
| F9 | 30A | Green | Starter Motor Relay |
| F10 | 10A | Red | A/C Clutch |
| F11 | 30A | Green | Trailer Brake Control |
| F12 | 25A | Natural | Wipers |
Relay Locations (Under-Hood)
- R1: Starter Relay
- R2: Ignition Main Relay
- R3: A/C Clutch Relay
- R4: Fuel Pump Relay
- R5: Blower Motor Relay
- R6: High Beam Relay
- R7: Low Beam Relay
In-Cab Dash Fuse Box
This fuse panel handles most of the interior and body control circuits. It is located behind a removable panel on the driver's side of the dashboard, often near the clutch or brake pedal.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 10A | Red | Instrument Cluster |
| F2 | 15A | Blue | Radio / Infotainment System |
| F3 | 10A | Red | Airbag / SRS Control Module |
| F4 | 15A | Blue | Turn Signals / Hazard Lights |
| F5 | 10A | Red | ECM / PCM (Ignition) |
| F6 | 15A | Blue | Tail / Park Lights |
| F7 | 10A | Red | Brake Light Switch |
| F8 | 20A | Yellow | Cigar Lighter / 12V Power Outlet 1 |
| F9 | 20A | Yellow | 12V Power Outlet 2 |
| F10 | 10A | Red | ABS Control Unit (Ignition) |
| F11 | 5A | Tan | Diagnostic Port Power |
| F12 | 15A | Blue | Dome Lights / Interior Lighting |
How to test a fuse
A blown fuse can cause a specific component or an entire system to stop working. Testing a fuse is a simple process.
- Turn off the ignition and the component in question.
- Locate the correct fuse box and remove the cover.
- Identify the suspect fuse. The diagram on the fuse box lid will help you find it.
- Remove the fuse. A fuse puller tool, often included in the fuse box, makes this easier than using your fingers or pliers, which can damage the fuse.
- Visually inspect the fuse. Look at the thin metal strip inside the plastic housing. If this strip is broken or melted, the fuse is blown and must be replaced.
- Confirm with a multimeter (optional but recommended). Set your multimeter to the continuity setting (it often looks like a sound wave symbol). Touch one probe to each blade of the fuse. If the multimeter beeps or reads close to zero, the fuse is good. If it remains silent or shows "OL" (Open Line), the fuse is blown.
When replacing a fuse, always use a new fuse with the exact same amperage rating. Using a higher-rated fuse can cause severe damage to the electrical system and create a fire hazard.
Common blown fuses on this vehicle
- Cigar Lighter / 12V Power Outlet Fuse: This is one of the most common fuses to blow. It is often caused by a faulty phone charger, a coin falling into the outlet, or plugging in a device that draws too much power. Before replacing the fuse, inspect the outlet for any foreign objects.
- Trailer Power / Trailer Brake Fuses: Issues with trailer wiring are a frequent cause. A short in the trailer's wiring harness or a faulty light can blow these fuses. If the fuse blows immediately upon connecting a trailer, the problem is almost certainly in the trailer's electrical system.
- Headlight Fuses: While less common than on older vehicles, a headlight fuse can blow. If one headlight goes out, check the bulb first. If both go out, the fuse or relay is a likely culprit. A recurring blown headlight fuse often points to a problem in the wiring harness or a faulty headlight assembly.
- Radio Fuse: If your infotainment system suddenly dies, the fuse is the first place to check. This can sometimes happen without a clear cause, but it may also be triggered by internal faults in the radio head unit.
Remember to consult the legend printed on your fuse box lid or in your owner’s manual to verify all fuse positions and ratings, as variations exist between different trim levels and manufacturing dates.
If you've checked the fuses and are still having trouble, it may be time for a professional diagnosis. Find a trusted shop on Repairius.
Before you pull a fuse on the 2018 International LT
- Use the label printed on the panel cover or the owner's manual for your exact build. Layouts change with options, model year and build date, so a chart for another truck can be wrong.
- Replace a blown fuse only with the same amp rating. A larger fuse can let wiring overheat.
- A fuse that blows again right away means a short or failing component downstream. Find the cause before replacing it again.
- A good fuse doesn't prove the circuit works — relays, grounds and connectors fail too.
- Many heavy trucks have more than one power distribution point (cab, under-hood or near the batteries), and some circuits use circuit breakers instead of fuses. Some systems have 24-volt starting circuits; confirm the voltage before testing.
- Disconnect the battery before working near high-current fuses or cables.
Learn more: How fuses, relays and truck electrical systems work · Find mobile truck repair
More specs for the 2018 International LT
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2018 International LT Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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