2018 Freightliner M2 106 Bulb Sizes

Quick reference

The 2018 Freightliner M2 106 is a versatile workhorse, and its lighting system is primarily halogen-based across most configurations. Some higher trim levels or specific options may feature integrated LED daytime running lights (DRLs) or other LED marker lights directly from the factory. It's important to note that the low and high beams in many M2 106 trucks share the same bulb size, H11.

LED vs halogen upgrade considerations

Upgrading the lighting on your 2018 Freightliner M2 106 from halogen to LED can offer significant benefits, including improved visibility, longer bulb lifespan, and a more modern appearance. However, there are several considerations to keep in mind to ensure a smooth transition.

CANBUS Errors: Modern vehicles, including the M2 106, use a Controller Area Network (CANBUS) system to monitor various electrical components, including lights. Halogen bulbs draw a specific amount of power, and when you replace them with lower-wattage LED bulbs, the CANBUS system might detect a difference in electrical resistance. This can trigger "bulb out" warnings or flickering lights on your dashboard. To circumvent these issues, you'll often need to use CANBUS-compatible LED bulbs or load resistors. Load resistors mimic the electrical load of a halogen bulb, tricking the CANBUS system into thinking the correct bulb is still in place.

Adapters Needed: While many aftermarket LED bulbs are designed for direct plug-and-play replacement, some may require specific adapters to fit securely into the existing bulb housing. This is particularly true for headlight and fog light upgrades. Always check the product specifications and any included instructions to ensure compatibility and the need for adapters or retainers. Some LED headlight kits may also include a separate driver module that needs to be mounted securely away from heat and moisture.

Beam Pattern and Legality: When upgrading headlights and fog lights to LED, pay close attention to the beam pattern. Poorly designed LED bulbs in a reflector housing can create excessive glare for oncoming drivers or have an unfocused beam pattern, reducing your own visibility. Opt for LED bulbs specifically designed for your reflector-style headlights or consider complete LED headlight assemblies if available and within your budget. Additionally, ensure that your chosen LED lights comply with local regulations and Department of Transportation (DOT) standards. Some jurisdictions have strict rules regarding aftermarket lighting.

How to replace each bulb

Replacing bulbs on your M2 106 is generally straightforward, but some locations require specific steps.

• Low Beam Headlight (H11): Access is usually from the rear of the headlight assembly under the hood. Twist the bulb counter-clockwise to remove, unplug the connector, and install the new bulb in reverse order.
• High Beam Headlight (H11): Similar to the low beam, access is from the rear of the headlight assembly.
• Fog Light (H10): Typically accessed from underneath the truck or by removing a fender liner. Twist to remove, disconnect, and replace.
• Front Turn Signal (3157/7443): Often accessible from behind the light housing, requiring a twist-and-pull motion to remove the socket.
• Rear Turn Signal, Brake, Tail Light (3157/7443): These are usually integrated into the tail light housing. Access is typically from the rear by removing screws or clips holding the lens in place, then twisting the relevant socket to remove the bulb.
• Reverse Light (3157/7440): Located within the tail light assembly, similar to the turn and brake lights.
• License Plate Light (168/194): These small bulbs are usually found in a small housing above the license plate. Pry off the cover (carefully) or remove small screws to access.
• Side Marker (168/194): Found on the side of the cab or body, often requiring careful prying to remove the lens and access the bulb.
• Dome/Map Light (578): Pry off the clear lens cover to access the bulb. Be gentle to avoid cracking the plastic.

Always ensure the vehicle is turned off, and the parking brake is engaged before attempting any bulb replacements. Refer to your owner's manual for specific instructions and diagrams relevant to your exact chassis configuration.

Common lighting issues for this generation

The 2018 Freightliner M2 106, while robust, can experience a few common lighting-related issues, typical of commercial vehicles enduring harsh environments and high mileage.

• Corrosion in Sockets: Exposure to moisture, road salt, and dirt can lead to corrosion in bulb sockets, especially for exterior lights. This can cause intermittent bulb operation, flickering, or complete bulb failure, even if the bulb itself is good. Regular inspection and cleaning of sockets with electrical contact cleaner can mitigate this.
• Vibration-Induced Bulb Failure: Commercial trucks experience significant vibration. Over time, this can cause halogen bulb filaments to break prematurely. If you frequently find yourself replacing the same bulb, consider checking the mounting of the light assembly for looseness or upgrading to more vibration-resistant LED alternatives.
• Wiring Harness chafing or Damage: The wiring harnesses on commercial trucks are exposed to various elements and movement. Chafing against frame components, heat, or accidental damage can lead to intermittent or complete loss of power to light circuits. Inspect visible wiring for any signs of wear or damage if you experience widespread lighting problems not attributable to individual bulbs.
• DRL Module Issues (if equipped): For trucks with factory-installed LED Daytime Running Lights, issues might arise with the DRL control module itself, rather than individual LEDs (which are typically long-lasting). If DRLs are flickering or not illuminating, and no obvious external damage is present, a diagnostic check of the DRL module might be necessary.

Find a trusted shop on Repairius.