2020 Kenworth T680 Fuse Box Diagram & Amperage

Quick Answer

The 2020 Kenworth T680 typically has three main fuse box locations: one under the hood, one in the dash kick panel (passenger side), and a third in the sleeper compartment.

Note: Fuse box configurations can vary slightly based on specific vehicle trim levels and optional equipment. Always refer to the fuse diagram printed on the inside of your fuse box cover for the most accurate information for your truck.

Under-Hood Fuse Box

The under-hood fuse box is primarily responsible for protecting high-current circuits and critical engine functions. It is usually located on the driver's side, near the firewall.

Under-Hood Relays:

The under-hood fuse box also houses several important relays:

• R1: Starter Relay
• R2: Fuel Pump Relay
• R3: High Beam Headlight Relay
• R4: Low Beam Headlight Relay
• R5: Blower Motor Relay
• R6: A/C Clutch Relay

Dash Kick Panel Fuse Box (Passenger Side)

The dash kick panel fuse box, typically located behind a removable panel on the passenger side footwell, handles many of the vehicle's interior electrical components and accessories.

Dash Kick Panel Relays:

• R1: Accessory Relay
• R2: Ignition Relay

Sleeper Compartment Fuse Box

The sleeper compartment fuse box primarily serves the various auxiliary components and conveniences found in the sleeper area. Its exact location can vary but is often found behind a panel near the bunk or storage areas.

Sleeper Compartment Relays:

• R1: Sleeper Accessory Relay
• R2: Inverter Relay

How to Test a Fuse

Testing a fuse is a straightforward process and a common first step in diagnosing electrical issues. Here's how:

1. Safety First: Always turn off the ignition and remove the key before working with fuses.
2. Locate the Fuse: Refer to your fuse box diagram to find the suspected fuse.
3. Visual Inspection: Most fuses are translucent. Look for a broken wire or burnt metallic strip inside. If it's visibly broken, the fuse is blown.
4. Use a Fuse Tester or Multimeter:
   • Fuse Tester: Insert the fuse into the tester. If the light illuminates, the fuse is good. If not, it's blown.
   • Multimeter: Set your multimeter to the continuity or ohms setting. Touch the probes to the metal contact points on top of the fuse. A good fuse will show very low resistance (close to 0 ohms) or indicate continuity (a beep). A blown fuse will show an open circuit (OL or infinite resistance).
5. Replace (if necessary): If the fuse is blown, replace it with a new fuse of the exact same amperage rating and color. Never use a higher-rated fuse, as this can lead to severe electrical damage or fire.

Common Blown Fuses on This Vehicle

While any fuse can blow, some are more prone to failure due to the nature of their circuits or common accessory usage. On a 2020 Kenworth T680, you might frequently encounter issues with:

• Cigar Lighter / 12V Power Outlets (Dash and Sleeper): These are often overloaded by devices like phone chargers, portable refrigerators, or other accessories. Check the fuse for the "Cigar Lighter" or "12V Outlet" (F3 in dash, F1 in sleeper) first if you have no power to your accessories.
• Blower Motor (Under-Hood F3): A failing blower motor or an obstruction in the HVAC system can cause the blower motor fuse to blow.
• Trailer Brake Controller (Under-Hood F13): Problems with trailer wiring or the trailer brake system itself can sometimes trip this fuse. Always inspect trailer wiring for shorts if this fuse blows repeatedly.
• Radio / Infotainment (Dash F1): Issues with aftermarket radio installations or internal faults in the head unit can cause this fuse to blow.

What to check first: If a fuse blows, consider what components were in use or recently connected to that circuit. For power outlets, remove all accessories before replacing the fuse. If a vital system like the headlights or ECM fuse blows, and you haven't recently added any new accessories, it's best to consult a professional technician as it could indicate a deeper electrical issue.

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