2020 Isuzu NPR Fuse Box Diagram & Amperage
Detailed diagrams and common troubleshooting for your 2020 Isuzu NPR's electrical system.
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Quick answer
The 2020 Isuzu NPR typically features three main fuse box locations: one under the hood, a second inside the cabin (usually on the driver's side kick panel), and a third in the cabin, often located behind the glove box.
Under-hood Fuse Box
The under-hood fuse box is the primary power distribution center, protecting high-current circuits and crucial engine components. It's usually found on the driver's side near the battery. Always consult the diagram on your fuse box lid for exact fuse locations and ratings, as variations can occur based on specific NPR configurations and optional equipment.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 10A | Red | ECM (Engine Control Module) Basic |
| F2 | 15A | Blue | Fuel Pump |
| F3 | 20A | Yellow | Ignition System |
| F4 | 30A | Green | Starter Relay |
| F5 | 10A | Red | Headlights Low Beam (Left) |
| F6 | 10A | Red | Headlights Low Beam (Right) |
| F7 | 15A | Blue | Headlights High Beam (Left) |
| F8 | 15A | Blue | Headlights High Beam (Right) |
| F9 | 10A | Red | Tail Lights / Parking Lights |
| F10 | 15A | Blue | ABS (Anti-lock Brake System) Solenoid |
| F11 | 20A | Yellow | Blower Motor (Main) |
| F12 | 10A | Red | A/C Clutch |
| F13 | 30A | Green | Trailer Brake (Electric Brake Controller) |
| F14 | 20A | Yellow | ECM (Engine Control Module) Power |
| F15 | 10A | Red | Transmission Control Module (TCM) |
| F16 | 10A | Red | O2 Sensor Heater |
| F17 | 15A | Blue | Horn |
| F18 | 10A | Red | Wiper Motor |
Relay Locations (Under-hood):
- Starter Relay: Energizes the starter motor.
- Fuel Pump Relay: Controls power to the fuel pump.
- ECM Relay: Provides power to the Engine Control Module.
- Headlight Relays (Low/High Beam): Control power to the respective headlight circuits.
- Cooling Fan Relay: Activates the engine cooling fan.
Cabin Fuse Box (Driver's Side Kick Panel)
This fuse box manages various interior electrical components and accessories. It's typically located behind a removable panel on the driver's side kick panel or lower dashboard. Again, always refer to your vehicle's specific fuse diagram for the most accurate information.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| C1 | 10A | Red | Radio / Infotainment System |
| C2 | 15A | Blue | Cigar Lighter / 12V Power Outlet (Front) |
| C3 | 10A | Red | Cabin Fuse (Interior Lights, Dome) |
| C4 | 10A | Red | ABS (Anti-lock Brake System) Controller |
| C5 | 10A | Red | Airbag System (Supplemental Restraint System) |
| C6 | 15A | Blue | Power Windows |
| C7 | 10A | Red | Turn Signals / Hazard Lights |
| C8 | 10A | Red | Brake Lights (Stop Lights) |
| C9 | 10A | Red | Instrument Cluster |
| C10 | 10A | Red | HVAC Control Panel |
| C11 | 10A | Red | Diagnostic Link Connector (DLC) |
| C12 | 15A | Blue | Accessory Power (ACC) |
| C13 | 20A | Yellow | Blower Motor (Cabin Fan) |
| C14 | 5A | Tan | Ignition Switch |
Relay Locations (Cabin - Driver's Side):
- Accessory Relay: Controls power to various accessories when the ignition is on.
- Blower Relay: Activates the cabin's heating and air conditioning blower motor.
Cabin Fuse Box (Behind Glove Box)
Some 2020 Isuzu NPR models, particularly those with more extensive electrical options or upfitted bodies, may have an additional fuse box located behind the glove box on the passenger side. This box often handles auxiliary systems, body builder circuits, or additional accessory power.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| G1 | 15A | Blue | Auxiliary Power Outlet (Cargo/Additional) |
| G2 | 10A | Red | Body Builder Upfit Circuits (e.g., liftgate) |
| G3 | 10A | Red | Rear A/C or Heater (if equipped) |
| G4 | 10A | Red | Trailer Lighting (additional, if equipped) |
| G5 | 10A | Red | Power Locks |
| G6 | 10A | Red | Heated Mirrors (if equipped) |
How to Test a Fuse
- Safety First: Ensure the vehicle's ignition is off and the battery is disconnected if you're working on high-current fuses or relays.
- Locate the Fuse: Remove the fuse box cover and consult the diagram to identify the fuse you want to test.
- Visual Inspection: Most fuses have a small wire or filament inside. If this wire is broken or melted, the fuse is blown. Tinted or opaque fuses may require an electrical test.
- Use a Fuse Tester or Multimeter:
- Fuse Tester: These inexpensive tools light up if the fuse is good. Simply touch the probes to the small metal test points on top of the fuse (without removing it).
- Multimeter: Set your multimeter to continuity mode (or ohms). Remove the fuse from its slot. Touch the probes to each metal blade of the fuse. A good fuse will show very low resistance or continuity (the multimeter might beep). If it shows infinite resistance or
Before you pull a fuse on the 2020 Isuzu NPR
- 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.
- Disconnect the battery before working near high-current fuses or cables.
Learn more: How fuses, relays and truck electrical systems work
More specs for the 2020 Isuzu NPR
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
2020 Isuzu NPR 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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