Freightliner Cascadia Headlight Replacement Guide (2014–2025)

Everything you need to know about replacing headlights on your Freightliner Cascadia — including bulb sizes, assembly options, and step-by-step installation.

Freightliner Cascadia Headlight Bulb Sizes by Year

One of the most common questions we get is "What headlight bulb does a Freightliner Cascadia take?" Here's the breakdown:

2008–2017 Cascadia (Pre-Facelift)

• Low Beam: H11 halogen (or LED H11 upgrade)
• High Beam: 9005 (HB3)
• Turn Signal: 3157A amber
• Parking Light: 168 / T10 wedge

2018–2025 Cascadia (New Generation)

• Low Beam: H11 LED (factory) or H11 halogen
• High Beam: 9005 (HB3)
• Daytime Running Light: LED (integrated)
• Turn Signal: 7440A amber

Note: Always verify with your VIN, as trim levels and factory options can vary.

When to Replace Your Cascadia Headlight Assembly

Bulb replacement is the easy fix, but sometimes the entire headlight assembly needs to go. Here are the common signs:

Moisture or condensation inside the housing — A cracked seal or hairline fracture in the lens lets water in. Once moisture is inside, it fogs up, dims your light output, and can corrode the wiring. No amount of drying fixes a broken seal.

Yellowed, hazy, or scratched lenses — UV damage from years on the road degrades polycarbonate lenses. This scatters your beam pattern and reduces visibility. Buffing kits are a temporary fix at best.

Cracked or broken housing — Road debris, parking lot incidents, or minor collisions can crack the housing. Even a small crack lets in water and dust.

Electrical issues — Corroded sockets, melted connectors, or wiring problems inside the assembly mean it's time for a full replacement rather than chasing intermittent faults.

Aftermarket vs. OEM: What's the Difference?

OEM Freightliner headlight assemblies from the dealer typically run $800–$1,500+ per side. For a working truck that needs to be back on the road, that's a lot of downtime cost on top of the part price.

Aftermarket headlight assemblies offer the same fitment and function at a fraction of the cost. Quality aftermarket units use:

• DOT/SAE compliant lenses
• OEM-spec mounting points for direct bolt-on installation
• Proper beam patterns that pass inspection
• UV-coated polycarbonate lenses

At EverTrust Parts, our Freightliner Cascadia headlight assemblies are built to OEM specifications and ship fast across North America.

How to Replace Freightliner Cascadia Headlights: Step by Step

Tools You'll Need

• 10mm socket and ratchet
• T30 Torx bit (some models)
• Flat-head screwdriver
• Clean microfiber cloth
• Electrical contact cleaner (recommended)

Pre-2018 Cascadia:

Step 1: Open the hood and locate the headlight assembly mounting bolts. There are typically 3-4 bolts holding the assembly in place — two on top and one or two on the side.

Step 2: Disconnect the electrical connectors behind the headlight. Press the release tab and pull straight back. Don't twist or pry — the connectors are fragile.

Step 3: Remove the mounting bolts. Support the headlight assembly with your other hand as you remove the last bolt so it doesn't fall.

Step 4: Carefully pull the assembly forward and out. Watch for any remaining clips or brackets.

Step 5: Transfer any components from the old assembly to the new one if needed (bulbs, adjusters, brackets).

Step 6: Install the new assembly in reverse order. Start the bolts by hand before tightening to avoid cross-threading.

Step 7: Reconnect the electrical connectors until they click. Test all functions: low beam, high beam, turn signal, parking light.

Step 8: Aim your headlights. Park 25 feet from a wall or garage door, mark the center of each beam, and adjust using the built-in adjusters until the hot spot is slightly below and to the right of center.

2018+ New Generation Cascadia:

The process is similar, but the new generation has an integrated LED DRL module. Make sure your replacement assembly includes the DRL if your truck came with one from the factory. The mounting points are slightly different — there are typically 4 bolts and the bumper may need to be loosened (not removed) for access on some models.

LED Headlight Upgrades for Freightliner Cascadia

Upgrading to LED headlight bulbs is one of the best bang-for-your-buck modifications for any Cascadia. Benefits include:

• 3-5x brighter than stock halogen
• 50,000+ hour lifespan vs. 1,000 hours for halogen
• Lower power draw — less load on your electrical system
• Whiter light (6000K-6500K) — better visibility, less eye fatigue on night drives

When choosing LED bulbs, make sure they're specifically designed for truck headlights and have proper heat management (built-in fans or copper heat sinks). Cheap LEDs without adequate cooling will fail prematurely.

Freightliner Cascadia Headlight Fuse Location

If your headlights aren't working at all, check the fuse first before replacing anything:

• Pre-2018 Cascadia: The headlight fuses are in the main fuse panel on the driver's side dash, behind a removable cover. Look for fuses labeled "HDL LO" and "HDL HI." They're typically 15-20 amp fuses.
• 2018+ Cascadia: The fuse box is in a similar location on the driver's side. Consult your owner's manual for the exact fuse positions, as they can vary by build date.

Pro tip: If a fuse keeps blowing, don't just replace it with a higher-rated fuse. There's an underlying short or wiring issue that needs to be traced and fixed.

Common Freightliner Cascadia Headlight Problems

One headlight dimmer than the other: Usually a failing bulb, corroded ground wire, or a bad connection at the socket. Clean the contacts first, then try swapping the bulbs side to side to confirm it's the bulb and not the wiring.

Headlights flicker at idle: Typically caused by a weak alternator, loose battery connection, or a ground issue. Check your voltage at idle — it should be 13.5-14.5V.

High beams work but low beams don't (or vice versa): Bad bulb, blown fuse, or a failing headlight switch. These are separate circuits, so troubleshoot each independently.

Moisture inside new headlights: Some condensation after washing or rain is normal and should clear within a few hours of driving. If it persists, check that all rubber grommets and dust covers are properly seated.

Shop Freightliner Cascadia Headlights at EverTrust Parts

We carry aftermarket headlight assemblies for Freightliner Cascadia (2008–2025), plus headlights for Kenworth, Peterbilt, Hino, Isuzu, and more.

Why truck owners choose EverTrust:

• OEM-quality fitment at aftermarket prices
• Fast shipping across North America (USA & Canada)
• Real truck parts expertise — we know these trucks

Browse Freightliner Headlights →

Need help finding the right headlight for your Cascadia? Contact us at sales@evertrustparts.com and include your truck's year and VIN — we'll match you with the right part.

Related: Peterbilt 389 grille assembly | Peterbilt 389 headlight housing