Finding the Right Bulb for Your 2018–2020 Ford F-150: A Practical Buyer’s Approach

Most F-150 owners start their bulb search with one question: “What size headlight bulb does my truck take?” But the headlights are only one piece of the puzzle. Fog lights, front turn signals, and reverse lights each have their own sizing — and in some cases, that sizing changes depending on whether you’re looking at a 2018 model or a 2019–2020 model.

Rather than guessing from memory or trusting a generic online chart, it helps to work through three questions before you buy anything:

1. What year is the truck?
2. Which light are you replacing?
3. Does the truck have factory halogen, HID, or LED lighting?

Below is a breakdown of the bulb sizes typically found on 2018–2020 F-150 models with factory halogen setups, along with the reasoning you’ll want to apply before installing anything.

The Bulb Sizes at a Glance

For trucks with factory halogen lighting, the sizes most commonly reported are:

Treat this table as a reference point, not a guarantee. Trucks with factory HID or LED headlights, aftermarket housings, or trim-specific packages can deviate from it entirely. If you want to browse options after confirming your setup, Lasfit’s LED lights for Ford F-150 collection is a reasonable place to compare products against your confirmed bulb size.

Working Through Each Position

Low Beam (H11)

The low beam does the heavy lifting on most nighttime drives — lighting the road ahead without blinding oncoming traffic. Before swapping this bulb, walk through this checklist:

• Confirm the truck has factory halogen headlights (not HID or LED).
• Check that the removed bulb is actually marked H11.
• Make sure the replacement locks securely into the factory socket.
• Verify there’s clearance behind the bulb for any cooling hardware.
• Confirm the dust cover can still close fully.
• Check that the light source sits in the same position the original filament did.
• Test that the low-beam cutoff line stays sharp and controlled after install.

A bulb’s advertised brightness tells you very little. What matters is whether the housing — designed around a halogen filament — can properly shape the light from a different source. Mismatched positioning inside the reflector can throw too much light at your hood and too little down the road.

High Beam (9005/HB3)

High beams exist for the situations low beams can’t handle: unlit backroads, open highway at night, anywhere you won’t be blinding another driver. The 9005 bulb (also labeled HB3) is the common factory-halogen size here.

Things worth checking when choosing a replacement:

• Does the beam stay tightly focused ahead of the truck, or does it scatter?
• Is there a noticeable improvement in how far you can see?
• Are the left and right sides evenly matched?
• Does the bulb seat securely?
• Will any added cooling components fit inside the factory housing?
• Does performance hold up with repeated on/off cycles?

If you’re replacing both the H11 and 9005 bulbs at once, try to match color temperature between them. A visible tone mismatch between low and high beam looks unfinished and can be distracting at night. Anyone shopping specifically for a matched pair should look at 2018/2019/2020 f150 led headlights built for the H11/9005 factory-halogen configuration — just confirm your truck matches that setup first.

Fog Light (H10/9145)

Mounted lower than the headlights, fog lights are built for short-range visibility in rain, fog, snow, or dust — conditions where a longer beam just bounces light back at you. The common size here is H10, sometimes labeled 9145.

Before installing:

• Confirm the truck actually came with fog lights from the factory.
• Check the base marking against H10/9145.
• Inspect the housing for moisture intrusion or cracks.
• Watch for aim that’s too high after the swap.
• Make sure the factory seal isn’t compromised during install.

A common mistake is chasing the whitest, highest-output bulb available. In fog or heavy rain, that extra brightness often scatters off airborne moisture and reflects straight back at the driver. Controlled, close-range output beats raw brightness in these conditions.

Front Turn Signals — Where Year Matters Most

This is the position most likely to trip up a buyer, because the correct bulb changes between model years:

• 2018 F-150: 7443
• 2019–2020 F-150: 4257A

Even if every other bulb size on your truck stays consistent, don’t assume the turn signal does too — always verify against your specific year.

One other issue to watch for: switching to an LED turn-signal bulb can trigger hyperflashing, where the signal blinks faster than normal because the truck’s electrical system reads a lighter load than expected. A bulb that physically fits the socket isn’t necessarily electrically compatible with the vehicle. And regardless of any styling goals, the signal still needs to read as a clear amber color — cosmetic tinting shouldn’t come at the expense of visibility to other drivers.

Reverse Light (7443)

The reverse light size most often listed for 2018–2020 trucks is 7443. It matters more than owners sometimes assume, especially for anyone who:

• Hitches or unhitches a trailer after dark
• Backs into an unlit driveway or garage
• Parks at a campsite without external lighting
• Works around a jobsite, farm, or warehouse at night
• Relies on a backup camera for tight maneuvers

When judging a reverse-light bulb, focus on how well it lights up the ground and area behind the truck — not how intense it looks when you stare directly at it. A bulb that throws light in a narrow beam may not make good use of the reflective housing behind it. Test it in a genuinely dark setting, including a check of how it affects the backup camera feed.

Why Two Trucks From the Same Year Can Need Different Bulbs

It’s easy to assume “2019 F-150” is enough information to find a bulb. It usually isn’t, for a few reasons:

Factory lighting type varies. Halogen, HID, and factory LED all exist across 2018–2020 trucks, and H11/9005 sizing generally applies only to the halogen setups.

Trim level isn’t a reliable shortcut. XL, XLT, Lariat, and other trims can carry different lighting equipment or optional packages, so the trim name alone doesn’t confirm fitment.

Previous owners may have swapped assemblies. A truck with aftermarket headlight housings may no longer use the original factory bulb size — sometimes H1 or H7 instead. If you’re not the first owner, inspect what’s actually installed rather than trusting a lookup by year.

Online bulb databases are often too generic. Many tools only ask for year and model, without accounting for halogen vs. HID vs. LED or trim-specific hardware. Use them as a starting point, not a final answer.

A Simple Verification Process Before You Order

1. Check the owner’s manual. It usually lists any driver-replaceable bulbs. Integrated LED assemblies may not have a traditional bulb number at all.
2. Pull the old bulb and read it. This is the most reliable check available. Look for markings like H11, 9005, H10, 7443, or 4257A — and let the bulb cool first, avoiding bare-finger contact with halogen glass.
3. Identify the factory lighting type. Cross-reference the build sheet, VIN configuration, or the physical housing itself to confirm halogen, HID, or LED.
4. Look for signs of prior modification. If the headlight housings don’t look stock, check what’s currently installed before ordering anything new.
5. Use fitment tools as a cross-check, not a final answer. Compare any online lookup against the manual and the physical bulb in hand.

Deciding Where to Start

Not every owner needs to upgrade every position at once. A reasonable way to prioritize:

• Start with the low beams if general nighttime visibility is your main concern, or if the factory beams already look dim or uneven.
• Add the high beams if you regularly drive dark rural roads and want longer-range visibility, or if your current low/high beams look mismatched.
• Add fog lights if you frequently deal with rain, fog, snow, or dust and need better close-range lighting.
• Replace turn signals if the originals are failing or discolored — just be ready to check for hyperflashing afterward.
• Replace reverse lights if you tow, park, or work in dark conditions regularly, or if your backup camera struggles at night.

Installing bulbs one position at a time, rather than all at once, makes it much easier to trace the source if you run into flickering, hyperflashing, or a dashboard warning light afterward.

What to Check After Installation

Turning the light on isn’t the finish line. Once everything’s installed, verify:

• The low-beam cutoff is still sharp and controlled
• Both headlights are aimed evenly
• High beams point forward, not upward or off to the side
• Fog lights stay close-range and controlled
• Turn signals blink at a normal rate (no hyperflashing)
• Turn signals still show true amber
• Reverse lights noticeably improve visibility behind the truck
• Dust covers close all the way
• Weather seals are intact
• No warning lights appear on the dash
• Output stays steady with no flickering after extended use

A quick way to catch alignment problems: park facing a flat wall on level ground and compare the beam patterns side by side. If one side sits noticeably higher, lower, or blurrier than the other, double-check that both bulbs are fully seated before touching the headlight aim adjustment.

Bottom Line

For factory-halogen 2018–2020 F-150s, the commonly cited sizes are H11 (low beam), 9005/HB3 (high beam), H10/9145 (fog light), and 7443 (reverse light) — with the front turn signal splitting by year: 7443 for 2018, 4257A for 2019–2020.

None of that replaces a physical check of your own truck. Factory HID systems, factory LED systems, and aftermarket housings can all break from the standard sizing above. Pulling the old bulb, reading the owner’s manual, and confirming your factory lighting type will get you a more reliable answer than any generic chart — and it’s the difference between a clean installation and one that leaves you dealing with poor beam patterns, hyperflashing, or a seal that won’t close.