2020 International MV Fuse Box Diagram & Amperages

As an ASE-certified master technician, I know that dealing with electrical gremlins on a commercial truck can bring your route to a grinding halt. The 2020 International MV is a workhorse medium-duty truck, but like any modern vehicle, its complex electrical systems are protected by a network of fuses and relays. Finding the right fuse quickly can mean the difference between getting back on the road and calling a heavy-duty tow truck.

This guide provides a comprehensive breakdown of the fuse box locations, amperage ratings, and circuits for the 2020 International MV series.

Disclaimer: Commercial trucks have highly customized electrical systems based on upfitter body prep, engine choices (Cummins B6.7 or L9), and trim levels. Always verify with the printed legend on the inside of your specific fuse box lid or your fleet maintenance manual.

Quick Answer: Fuse Box Locations

On the 2020 International MV, the fuses and relays are primarily divided into two main areas:

1. Under-Hood Power Distribution Module (PDM): Located on the driver's side of the engine compartment, mounted on the firewall or inner fender well. This handles high-draw components, engine management, and exterior lighting.
2. Cab / Dash Fuse Panel: Located inside the cab, typically behind a removable panel on the passenger side dash or lower kick panel area. This panel protects cabin accessories, infotainment, climate control, and body control functions.
3. Battery Box Fuses (Mega Fuses): Mounted directly in or near the battery box on the chassis frame rail, these protect the main starter cable, alternator feed, and primary power lines to the cab.

Under-Hood Power Distribution Module (PDM)

The under-hood PDM is the nerve center for the truck's engine, drivetrain, and primary exterior functions. Be sure to check this box first for engine-related codes, fuel delivery issues, or ABS faults.

Under-Hood Relays

Alongside the fuses, the PDM houses several critical micro-relays and mini-relays:

• R1: Starter Motor Relay
• R2: Fuel Pump Relay
• R3: ECM Main Power Relay
• R4: A/C Clutch Relay
• R5: Trailer Tow Relay

Cab / Dash Fuse Panel

Located inside the cabin, this fuse block routes power to driver comforts, the gauge cluster, and interior electronics.

How to Test a Fuse

Blowing a fuse on a commercial route is stressful, but testing them is quick and straightforward. You do not always need to pull a fuse to test it.

1. Use a 12V Test Light or Multimeter: Ground the clip of your test light to a good chassis ground (or set your multimeter to DC Volts).
2. Turn the Key to the 'ON' Position: Some circuits only receive power when the ignition is on.
3. Probe the Test Points: Look at the top of the fuse. You will see two tiny metal test points exposed on the plastic housing.
4. Check Both Sides: Probe both sides of the fuse. If the test light illuminates (or the meter reads ~12V) on both sides, the fuse is good. If it lights up on one side but not the other, the fuse is blown and must be replaced.
5. Always Replace with the Same Amperage: Never substitute a higher-amp fuse (e.g., swapping a 10A for a 30A). This can melt wiring harnesses or cause an electrical fire.

Common Blown Fuses on the 2020 International MV

Because these trucks serve diverse roles—from box trucks to dump trucks to wreckers—certain circuits are put under heavy strain.

• Cigar Lighter / 12V Outlets (Fuse C3): In commercial trucks, drivers often plug in high-draw accessories like portable coolers, inverters, or GPS units. If your cabin accessories suddenly die, check this 20A fuse first.
• Trailer Tow Fuses (Fuse F8 / F14): Constantly connecting and disconnecting trailers with questionable wiring often leads to blown trailer light and brake fuses. Always inspect the pigtail connection at the back of the truck for corrosion or bent pins.
• Blower Motor (Fuse C1): The HVAC blower works overtime in heavy trucks. If your A/C or heat stops blowing, check this 30A fuse. If it keeps blowing, the blower motor itself may be drawing too much current due to worn bearings.
• Upfitter / Body Builder Fuses (C11/C12): If your liftgate, PTO, or dump body controls suddenly lose power, check the auxiliary feeds provided for body builders. Ensure the upfitter wiring hasn't chafed against the chassis frame rails.

If you keep blowing the same fuse, you have a short circuit that needs professional diagnosis. Don't risk a roadside breakdown or an electrical fire. Find a trusted shop on Repairius.