2023 Peterbilt 579 Fuse Box Diagram & Amperage
Detailed Diagrams for Under-Hood, Dash, and Bunk Fuse Boxes
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Quick Answer
The 2023 Peterbilt 579 typically features multiple fuse box locations to manage its extensive electrical systems. You'll find fuse boxes located under the hood (engine compartment), inside the cabin (usually behind a kick panel on the passenger side or near the steering column), and potentially within the bunk or sleeper area for certain configurations.
Under-Hood Fuse Box
The under-hood fuse box on your 2023 Peterbilt 579 is primarily responsible for protecting high-current circuits and critical engine functions. This box often houses fuses and relays for the engine control module (ECM), fuel pump, starter relay, ABS system, and major lighting circuits.
Always verify the exact layout with the diagram printed on the inside of your fuse box cover, as configurations can vary slightly due to trim levels and optional equipment.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 20A | Yellow | ECM (Engine Control Module) Power |
| F2 | 15A | Blue | Fuel Pump Relay Control |
| F3 | 30A | Green | ABS Module Power |
| F4 | 20A | Yellow | Headlights - Low Beam (Left) |
| F5 | 20A | Yellow | Headlights - Low Beam (Right) |
| F6 | 15A | Blue | Headlights - High Beam (Left) |
| F7 | 15A | Blue | Headlights - High Beam (Right) |
| F8 | 25A | Clear | Blower Motor (HVAC) |
| F9 | 10A | Red | Ignition Switch |
| F10 | 20A | Yellow | Starter Relay Control |
| F11 | 15A | Blue | A/C Clutch Relay Control |
| F12 | 10A | Red | Tail/Parking Lights (Left) |
| F13 | 10A | Red | Tail/Parking Lights (Right) |
| F14 | 20A | Yellow | Trailer Brake Controller Power |
Relay Locations (Under-Hood):
- Starter Relay: Controls the starter motor engagement.
- Fuel Pump Relay: Powers the fuel pump.
- Headlight Relays: Separate relays often exist for low and high beams.
- ABS Relay: Powers the ABS control module.
Dash / Cabin Fuse Box
The dash or cabin fuse box, typically located behind a kick panel on the passenger side or drivers side near the steering column, manages electrical components within the interior of the truck. This includes fuses for the radio, infotainment system, interior lights, power windows, and auxiliary power outlets.
Refer to the specific diagram on your fuse box cover for precise locations, as exact numbering and circuit assignments can vary by model year and trim.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 15A | Blue | Radio / Infotainment System |
| F2 | 10A | Red | Instrument Cluster |
| F3 | 20A | Yellow | Cigar Lighter / 12V Outlet (Dash) |
| F4 | 20A | Yellow | 12V Accessory Outlet (Console) |
| F5 | 10A | Red | Brake Lights |
| F6 | 15A | Blue | Wiper Motor |
| F7 | 10A | Red | Interior Dome Lights |
| F8 | 15A | Blue | Power Windows |
| F9 | 10A | Red | HVAC Control Module |
| F10 | 10A | Red | Airbag System (SRS) |
| F11 | 15A | Blue | Auxiliary Power Unit (APU) Control (if equipped) |
| F12 | 10A | Red | Diagnostic Port (OBD-II/J1939) |
Relay Locations (Cabin):
- Accessory Relay: Controls various cabin accessories.
- Wiper Relay: Manages wiper motor operation.
Trunk / Bunk Area Fuse Box (If Equipped)
Some 2023 Peterbilt 579 models, especially those with sleeper configurations, may include an additional fuse box in the bunk or trunk area. This box typically manages electrical components specific to the sleeper cabin, such as auxiliary lighting, refrigeration units, power outlets, and entertainment systems within the bunk.
Always check your owner's manual or the fuse box cover for the exact layout and component assignments, as these can vary significantly based on the sleeper package and installed options.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| F1 | 20A | Yellow | Bunk Refrigerator (if equipped) |
| F2 | 15A | Blue | Bunk Power Outlet (12V) |
| F3 | 10A | Red | Bunk Interior Lights |
| F4 | 15A | Blue | Bunk HVAC Blower Fan |
| F5 | 20A | Yellow | Sleeper Entertainment System |
| F6 | 10A | Red | Auxiliary Heater Control (bunk) |
| F7 | 10A | Red | Alarm System (sleeper) |
How to Test a Fuse
Testing a fuse is a straightforward process. You will need a fuse puller (usually found in the fuse box lid or with your vehicle
Before you pull a fuse on the 2023 Peterbilt 579
- 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 2023 Peterbilt 579
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
2023 Peterbilt 579 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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Values can vary by engine, trim and build date; check your VIN-specific service information. Updated 2026-06-26.