2018 Volvo VNR Bulb Size Guide

Quick Reference

The 2018 Volvo VNR, a testament to modern trucking efficiency and design, primarily utilizes an advanced LED lighting system for its crucial exterior illumination. This choice reflects Volvo's commitment to durability, visibility, and energy efficiency, which are paramount in commercial trucking. While the majority of critical exterior lights are LED from the factory, some supplementary and interior lighting still rely on traditional incandescent bulbs, offering a mix of technologies.

LED vs. Halogen Upgrade Considerations

Given that many of the primary exterior lights on the 2018 Volvo VNR are already LED from the factory, "upgrading" these to aftermarket LEDs isn't usually a consideration for the headlights, fog lights, and DRLs. However, for those incandescent bulbs remaining – such as the rear turn signals, brake lights, reverse lights, and interior lights – an LED upgrade can offer significant benefits in terms of brightness, longevity, and reduced power consumption.

When considering LED replacements for the incandescent bulbs, it's crucial to be aware of potential CANBUS (Controller Area Network Bus) errors. Modern vehicles, including the VNR, utilize CANBUS systems to monitor various electrical components. Incandescent bulbs draw more power than LEDs, and if the system detects a lower power draw from an LED replacement, it may interpret this as a burned-out bulb, triggering a dashboard warning light. To avoid this, "CANBUS-compatible" LEDs or load resistors may be necessary. These resistors mimic the electrical load of an incandescent bulb, preventing error messages.

Furthermore, ensure that any aftermarket LED bulbs you choose are designed for the specific application (e.g., a 3157 LED for a 3157 incandescent socket). While the fitment might be similar, the beam pattern and light distribution can vary significantly. Quality aftermarket LEDs often come with built-in drivers and proper heat management to ensure optimal performance and lifespan.

How to Replace Each Bulb

Replacing bulbs on a commercial truck like the Volvo VNR can sometimes be more involved than on a passenger vehicle due to the size and integration of components. Always ensure the truck's power is off and disconnect the battery if working on electrical components.

• Headlights (Low/High Beam), Fog Lights, DRL, Front Turn Signal: As these are OEM LED units, replacement typically involves replacing the entire assembly if a component fails, rather than a single bulb. This is a more complex procedure often best handled by a qualified technician or dealership.
• Rear Turn Signal, Brake Light, Reverse Light: These 3157 incandescent bulbs are usually accessed from the rear of the tail light housing. Unclip or unscrew the lens assembly, twist the bulb holder to remove, and pull out the old bulb. Push in the new bulb, twist the holder back in, and reattach the lens.
• License Plate Light: The 194 bulb is typically housed in a small fixture near the license plate. Access is usually by removing a couple of screws or prying open a cover. Remove the old bulb and insert the new one.
• Side Marker Light: Similar to license plate lights, the 194 side marker bulbs are usually accessible by removing a small lens cover or by reaching behind the housing. Twist out the bulb holder, replace the bulb, and reassemble.
• Dome/Map Light: Interior lights vary in access. For the 921 dome/map lights, you usually gently pry off the clear plastic lens cover with a plastic trim tool. The bulb can then be pulled straight out and the new one pushed firmly into place. Be careful not to bend the contacts.

Common Lighting Issues for this Generation

While the 2018 Volvo VNR benefits from the reliability of OEM LED lighting for many primary functions, issues can still arise. One common concern even with robust LED systems can be moisture intrusion into headlight or tail light assemblies, leading to condensation and potentially affecting the LED performance or lifespan. Cracking or hazing of the plastic lenses over time, though less common with newer LED units, can also diminish light output.

For the incandescent bulbs, standard issues like filament breakage due to vibration (a common challenge in trucking) or corrosion in the bulb sockets can occur. Periodically checking all lights for proper operation is a crucial part of routine maintenance for commercial vehicles.

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