2017 Peterbilt 389 Fuse Box Diagram & Amperages

The 2017 Peterbilt 389 is an iconic heavy-duty truck known for its classic styling and robust performance. Whether you are hauling freight cross-country or running heavy vocational applications, electrical issues can bring your rig to a sudden halt. Knowing where your fuse boxes are located and what circuits they protect is critical for minimizing downtime.

Below is a comprehensive guide to the fuse box locations, amperage ratings, and common circuits for the 2017 Peterbilt 389. Note: Fuse configurations can vary based on your specific engine (PACCAR MX-13, Cummins ISX), sleeper configuration, and dealer-installed options. Always verify with the printed legend on the inside of your fuse box lid.

Quick Answer: Fuse Box Locations

On a standard 2017 Peterbilt 389, you will typically find the fuses and relays split across three primary locations:

1. Cab Lower Dash / Kick Panel Panel: Located inside the cab on the driver’s side, usually behind a removable panel near the clutch pedal or lower left dash area. This handles most interior and accessory circuits.
2. Under-Hood Power Distribution Center (PDC): Located in the engine bay, typically mounted on the driver's side firewall. This box manages high-draw engine, powertrain, and exterior lighting circuits.
3. Sleeper Fuse Panel (If Equipped): Located in the sleeper compartment, usually under the lower bunk or behind a side access panel. This controls sleeper HVAC, interior sleeper lights, and sleeper 12V accessories.

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Under-Hood Power Distribution Center (PDC)

The under-hood PDC handles the heavy lifting for the engine, ECM, ABS, and primary exterior lighting. Relays for the starter, ECM power, and fuel pump are also housed here.

Fuse #	Amp	Color	Circuit / Component Protected
F1	30A	Green	Engine Control Module (ECM) Power
F2	20A	Yellow	Fuel Pump / Lift Pump
F3	20A	Yellow	ABS / Bendix Trailer ABS Power
F4	15A	Blue	Headlights (Low Beam - Left)
F5	15A	Blue	Headlights (Low Beam - Right)
F6	20A	Yellow	Headlights (High Beams)
F7	10A	Red	Ignition Coil / Ignition Switch Feed
F8	30A	Green	Starter Relay Feed
F9	15A	Blue	A/C Compressor Clutch
F10	25A	Clear	Engine Cooling Fan Hub
F11	20A	Yellow	Transmission Control Unit (if automated)
F12	20A	Yellow	Trailer Brake / Marker Lights Feed
F13	10A	Red	Horn
F14	30A	Green	Cab Main Power Feed 1
F15	30A	Green	Cab Main Power Feed 2

Relay Locations in PDC: Typically, you will find large standard ISO relays for the Starter, Fuel Pump, ECM Power, A/C Clutch, and High Beams located directly adjacent to these fuses.

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Cab Dash / Kick Panel Fuse Box

This panel is responsible for the comfort, infotainment, and standard operator controls inside the cabin.

Fuse #	Amp	Color	Circuit / Component Protected
C1	15A	Blue	Radio / Infotainment / Navigation
C2	20A	Yellow	Cigar Lighter / 12V Power Outlet
C3	30A	Green	Cab HVAC Blower Motor
C4	10A	Red	Instrument Cluster / Gauges
C5	15A	Blue	Turn Signals / Hazard Flashers
C6	15A	Blue	Cab Interior Dome / Map Lights
C7	10A	Red	CB Radio Power Prep
C8	20A	Yellow	Power Windows (Left/Right)
C9	15A	Blue	Power Door Locks
C10	10A	Red	Diagnostic Link Connector (OBD/9-Pin)
C11	15A	Blue	Heated Mirrors
C12	10A	Red	Airbag / SRS Module (If equipped)
C13	20A	Yellow	Windshield Wipers / Washer Pump
C14	15A	Blue	Tail / Park Lights / Clearance Lights
C15	20A	Yellow	Brake Lights / Stop Lamp Switch

Relay Locations in Cab: Relays for the Blower Motor, Wipers, and Turn Signal Flasher are usually integrated into this block or mounted just above it under the dash.

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Sleeper Compartment Fuse Panel

If your 2017 Peterbilt 389 is equipped with a sleeper, this secondary panel isolates sleeper accessories so they don't overload the main cab harness.

Fuse #	Amp	Color	Circuit / Component Protected
S1	30A	Green	Sleeper HVAC Blower Motor
S2	15A	Blue	Sleeper Interior Lighting
S3	20A	Yellow	Refrigerator Power Feed
S4	20A	Yellow	Sleeper 12V Outlets / Inverter Prep
S5	10A	Red	Sleeper Radio / Clock Memory
S6	15A	Blue	Sleeper Power Windows (if equipped)

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How to Test a Fuse

When electrical components fail on a heavy-duty truck, checking the fuses is step one. Here is the best way to test them:

1. Visual Inspection: Pull the suspected fuse using a fuse puller or needle-nose pliers. Look at the U-shaped metal element inside the colored plastic. If the metal is broken, burned, or melted, the fuse is blown and must be replaced.
2. Use a Multimeter or Test Light (Recommended): The most accurate way to test a fuse without removing it is using a digital multimeter or a 12V test light. Turn the ignition to the ON position (do not start the engine). Touch the test light probe or multimeter leads to the two small metal test points on the top of the fuse.
   • If the test light illuminates on both sides, the fuse is good.
   • If it lights up on one side but not the other, the fuse is blown.
   • If it lights up on neither side, the circuit is not currently receiving power (check relays, switches, or ignition state).

Warning: Never replace a blown fuse with one of a higher amperage rating. Doing so can cause melted wiring, damaged modules, or a vehicle fire.

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Common Blown Fuses on this Vehicle

Heavy-duty trucks endure intense vibrations and harsh environments, leading to specific electrical weak points. On the 2017 Peterbilt 389, watch out for:

• Trailer Marker/Brake Lights (PDC F12 or Cab C15): The pigtail connecting the tractor to the trailer is notoriously prone to corrosion, water intrusion, or being crushed. If you lose trailer lights, inspect the 7-way connector and cable before replacing the fuse.
• Cigar Lighter / 12V Outlet (Cab C2): Drivers frequently plug in high-draw devices like heavy-duty chargers, coolers, or small heaters into the standard 12V dash outlet. If these pull more than 20 amps, the fuse will pop. Consider wiring heavy draw accessories directly to the sleeper inverter panel.
• A/C Compressor Clutch (PDC F9): Over time, the A/C compressor clutch coil resistance can change due to engine heat, causing it to draw excess current. If this fuse blows repeatedly, the A/C clutch coil likely needs to be replaced.
• Lift Pump / Fuel Pump (PDC F2): Gelling fuel in the winter or a clogged fuel filter can cause the lift pump to work harder, over-drawing current and popping the fuse. Always check your fuel filters first if this fuse blows.

Electrical issues can be incredibly frustrating to track down, especially if a fresh fuse blows immediately upon replacement—indicating a direct short to ground.

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