2022 Kenworth T680 Bulb Sizes

Quick reference

The 2022 Kenworth T680, a popular choice for long-haul trucking, offers a variety of lighting configurations depending on trim level and factory options. Kenworth has been increasingly incorporating LED technology into its vehicles, which means you may find either traditional halogen bulbs or advanced LED units from the factory. Understanding your specific configuration is key when considering replacements or upgrades.

For headlights, the T680 typically uses H11 for low beams and H9 for high beams in models equipped with halogen systems. However, many T680s come with factory LED headlights, which integrate the low and high beams into a sealed LED unit. These LED headlights offer superior brightness and longevity but are generally not user-serviceable at the individual bulb level; if an LED unit fails, the entire assembly usually needs replacement. Fog lights can vary, with some T680s using H10 and others H16 halogen bulbs, or integrated LED fog lights. Always check your specific truck's existing bulb or owner's manual to confirm the correct size.

Daytime Running Lights (DRLs) on the 2022 T680 are almost always integrated LED strips or modules, offering the distinctive modern look associated with the T680. Front and rear turn signals, as well as brake and tail lights, commonly utilize 3157 bulbs, though factory LED taillight assemblies are also prevalent. If your truck has LED taillights, individual bulb replacement is often not an option. Reverse lights are also frequently 3157 or integrated LED. License plate lights and side markers typically use 194 bulbs or integrated LED units. Interior dome and map lights can vary, with common sizes being 578 or 212-2 festoon bulbs, or again, integrated LED panels.

LED vs halogen upgrade considerations

Upgrading from halogen to LED bulbs in your 2022 Kenworth T680 can significantly improve visibility and give your truck a more modern appearance. However, there are several factors to consider before making the switch.

CANBUS Errors: Modern trucks like the T680 use a CANBUS (Controller Area Network Bus) system to monitor electrical circuits. Halogen bulbs draw more power than LED bulbs, and if you replace a halogen bulb with an LED without an appropriate resistor or a CANBUS-compatible LED, the truck's computer may detect the lower power draw as a "bulb out" error. This can trigger dashboard warning lights or cause hyper-flashing for turn signals. To prevent this, look for "CANBUS error-free" LED bulbs or be prepared to install load resistors, which mimic the power draw of a halogen bulb.

Adapters Needed: While many aftermarket LED bulbs are designed for direct plug-and-play replacement, some may require specific adapters or wiring harnesses to properly connect to your T680's electrical system. This is particularly true for headlight upgrades where the LED bulb itself might have a larger heatsink or fan that requires more space behind the headlight assembly.

Beam Pattern and Legality: When upgrading headlights or fog lights to LED, ensure the beam pattern is correct. Poorly designed LED bulbs can scatter light, blinding oncoming drivers even on low beam. Opt for high-quality LEDs specifically designed for projector or reflector housings as applicable to your T680. Always check local regulations regarding vehicle lighting modifications to ensure your upgrade is street-legal.

How to replace each bulb

Replacing bulbs on your Kenworth T680 typically requires basic hand tools and a bit of patience. Always ensure the ignition is off and the lights are cool before attempting any bulb replacement.

• Headlights (Low/High Beam): Access is usually from behind the headlight assembly within the engine bay. Twist the bulb retainer counter-clockwise to remove the old bulb, disconnect the electrical connector, and reverse the process for the new bulb. For factory LED headlights, consult a professional for replacement of the entire assembly.
• Fog Lights: These are generally accessed from the front bumper area, often requiring removal of a cover or reaching underneath. Twist and pull (or unclip) the bulb, then disconnect the connector.
• DRL (Daytime Running Light): Since DRLs are almost always integrated LEDs, individual bulb replacement is not typically an option. If an LED segment fails, professional servicing of the entire DRL module or headlight assembly is usually required.
• Front Turn Signal: Access is often from the wheel well liner or behind the headlight assembly. Twist the socket to remove it from the housing, then pull the bulb straight out.
• Rear Turn Signal, Brake, Tail, Reverse Lights: These are commonly housed in the same taillight assembly. You'll usually need to remove a few screws holding the taillight lens in place to access the bulbs from the rear. Twist the bulb socket to remove it and pull out the old bulb.
• License Plate Lights: These are usually small housings above or near the license plate. Often involves removing a couple of screws to open the housing and access the bulb.
• Side Marker Lights: Similar to license plate lights, usually a small housing on the side of the truck. Unscrew or unclip to access.
• Dome/Map Lights: Carefully pry off the lens cover (often with a small flat-head screwdriver), being cautious not to scratch the plastic. The bulb can then be pulled straight out or unclipped depending on the type.

Common lighting issues for this generation

Owners of 2022 Kenworth T680 models have reported a few common lighting-related concerns, often tied to the increasing complexity of vehicle electronics and integrated LED systems.

LED Failure: While LEDs are known for their longevity, individual LED segments within an assembly can sometimes fail prematurely, particularly in less critical areas like DRLs or side markers. This typically requires replacing the entire module rather than a single bulb.

Moisture Ingress: Condensation or moisture buildup within headlight or taillight assemblies can occur, especially in regions with significant temperature fluctuations or high humidity. While minor condensation can sometimes evaporate, persistent moisture can lead to corrosion and premature bulb or LED unit failure.

CANBUS System Errors: As mentioned earlier, improperly installed aftermarket LED bulbs can trigger "bulb out" warnings or hyper-flashing due to the CANBUS system not recognizing the correct electrical load. This is a common issue for those upgrading from halogen to LED without appropriate CANBUS-compatible bulbs or load resistors.

Wiring Harness Issues: Although less common, wear and tear on wiring harnesses, especially in areas exposed to vibration or the elements, can lead to intermittent lighting problems or complete outages. Always inspect wiring for signs of chafing or corrosion if you're troubleshooting a persistent lighting issue.

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