2017 Volvo VNL Bulb Size Guide: Headlight, Tail, Fog & More

As an ASE-certified master technician who has spent countless hours under the tilting hoods of heavy-duty trucks, I know how critical reliable lighting is for commercial drivers. The 2017 Volvo VNL is a workhorse, but keeping it visible and safely illuminating the highway is an ongoing maintenance task. Whether your rig is equipped with the standard halogen composite housings or factory LEDs, having the correct bulb numbers on hand saves you precious downtime.

Below is your complete guide to the exterior and interior bulb sizes for the 2017 Volvo VNL.

Quick reference

Note: The 2017 Volvo VNL straddles the line between traditional halogen setups and the transition to full LED lighting. Fleet models typically utilize standard H11 halogens in projector low beams, while owner-operator or premium trim VNLs may feature integrated factory LED headlight assemblies.

LED vs halogen upgrade considerations

Upgrading your halogen H11 low and high beams to aftermarket LEDs provides exceptional visibility for night driving, but the Volvo VNL is notoriously picky when it comes to electrical upgrades.

The VNL utilizes a sensitive Light Control Module (LCM) that actively monitors circuit resistance to detect burnt-out bulbs. Because LEDs draw significantly less power than halogens, installing bare LED bulbs will almost certainly trigger a "Bulb Out" warning on your driver information display, and the LCM may cut power to the headlight entirely (causing flickering or shutting off).

To successfully upgrade:

• Use CANBUS Decoders: You must install heavy-duty CANBUS decoders/resistors inline with your new LED bulbs to trick the LCM into seeing the correct voltage draw.
• Clearance: Ensure the LED bulb's cooling fan or heat sink can clear the dust cap on the rear of the headlight housing. If the cap is left off, moisture will destroy the assembly.

How to replace each bulb

• Headlights (Low/High Beam): Tilt the hood forward. The composite headlight assemblies are fully accessible from the rear. Twist off the circular dust cap, unclip the wiring harness, and twist the H11 bulb counterclockwise to remove it.
• Fog Lights: Accessed from underneath the front bumper. If you have the aero bumper, you may need to remove an access panel or mud guard to reach the rear of the fog light housing.
• Front Turn Signal / DRL: Located within the main headlight assembly on most trims. Access is similar to the headlights—twist the socket counterclockwise to pull the 3157 bulb out.
• Rear Lighting (Brake/Turn/Tail/Reverse): Most 2017 VNLs use standard commercial 4-inch round sealed lights pushed into rubber grommets on the rear light bar. To replace, carefully pry the light out of the grommet with a flathead screwdriver and unplug the 3-prong pigtail connector. These cannot be opened; you must replace the entire sealed unit.
• Cab Marker/Clearance Lights: Many are sealed factory LED strips. If yours use replaceable 194 bulbs, remove the two Torx or Phillips screws holding the amber lens to the sun visor or cab roof.

Common lighting issues for this generation

The 2017 Volvo VNL generation is prone to a few specific lighting gremlins:

1. Light Control Module (LCM) Failures: If multiple lights on one side of the truck go out and the bulbs are fine, the LCM itself may require resetting, software updating, or complete replacement.
2. Wiring Harness Chafing: The wiring loom running along the frame rail to the rear tail lights often chafes against the frame, leading to shorts, blown fuses, and erratic tail light behavior.
3. Headlight Moisture: The seals around the composite headlight lenses dry out over time, allowing moisture inside. This can short out halogen bulbs prematurely. Check your dust caps and consider resealing the lens edges with silicone.

Keeping your rig out of the dark is a top priority. If you're dealing with stubborn LCM faults or electrical shorts you can't track down, don't waste hours on the shoulder. Find a trusted shop on Repairius.