LED Headlight Conversion Kits for Ford trucks and Mustangs: what to know before you buy

An LED headlight conversion kit swaps your halogen bulbs for LED bulbs in the housings you already have. It’s quick and plug-and-play, but in the US an LED bulb dropped into a halogen housing isn’t covered by the federal headlight standard, FMVSS 108. Kits like these are typically sold for off-road or auxiliary use, and both of ours are labeled that way. If you still want one, bulb size decides everything, so the tables below list F-150 and Mustang sizes by year.

Are LED headlight conversion kits legal?

Not for on-road headlight use, in the way most people mean the question. Here’s how it works.

FMVSS 108 treats a headlamp as a complete system: the housing, the optics and a specific light source. NHTSA’s interpretation, explained in a 2006 letter, says a replacement lamp is permitted if the vehicle maker could have certified the vehicle with it, including replacement headlamps that use a different light source. In plain terms, a complete assembly certified as a unit can qualify. A bulb on its own, put into a housing certified for halogen, doesn’t get that treatment.

Lighting sellers writing in 2026 say the same thing: aftermarket LED replacement bulbs in halogen housings aren’t federally compliant, there’s no certification path for them, and enforcement mostly falls to the states. “Off-road use only” labels are how many of these products are sold. A few listings call themselves “DOT approved,” but DOT doesn’t approve aftermarket parts, so read that claim skeptically.

States differ. Pennsylvania, for example, follows FMVSS 108 and inspects for aim, colour and glare.

Both kits we stock carry an off-road or auxiliary-use label. We sell them for what the label says.

What a conversion kit is, and what it isn’t

A kit replaces the bulb, not the housing. You get LED bulbs, usually with a heatsink or fan and a driver, and some include a CANbus-ready harness. It’s different from a complete LED headlight assembly, which replaces the housing, the optics and the light source together. The housing is what shapes the beam, and that’s why the two aren’t interchangeable.

Which bulb does your Ford use?

Check this before you shop. Pull your current bulb or check the owner’s manual to confirm, because sizes vary by year and trim.

F-150

Years	Low beam	High beam	Notes
2004–2014	H13 / 9008	H13 / 9008	One dual-filament bulb
2015–2020	H11	9005	Factory LED optional on some higher trims
2021 and up	H11	9005	Many higher trims have factory LED

Mustang

Years	Low beam	High beam	Notes
2005–2009	H13 / 9008	H13 / 9008
2010–2014	H11	H7	Halogen reflector models.
2015 and up	Factory LED	Factory LED	Halogen kits don’t apply.

If your truck or car has factory HID or factory LED headlights, don’t buy a conversion kit. These kits replace halogen bulbs in halogen housings only.

When an LED swap is a bad idea

• Your vehicle already has factory HID or LED headlights.
• You want to stay inside the federal standard on public roads.
• You live in a state that inspects, and the kit is labeled off-road only.
• You can’t confirm your bulb size.
• The rear heatsink or fan won’t fit: on 2015+ F-150s, the stock rubber dust cover may not seal over the extended LED body.
• You mainly want a bit more light. A higher-output halogen bulb made for your housing keeps the setup inside the original design.

The two kits we stock

.	Oracle High Output LED Conversion Kit	Sylvania LED Headlight Bulb 9005SLBX2
Price	$186	$100
Fits	Typically H11/9005 or H13	9005 (HB3). On a 2015+ F-150 that’s the high beam. Low beam only on select reflector setups
In the box	2 bulbs, external driver units, built-in fans, CANbus-ready harness	2 bulbs with integrated cooling and plug-and-play connectors
Output (manufacturer)	about 4,000–6,000 lumens per bulb, 6000K	about 1,500–2,000 lumens per bulb, 6000K
Warranty	2-year limited	1-year limited
Label	Off-road and fog / auxiliary light use only	Off-road / fog light use only

A word on the lumen numbers. Sylvania rates a standard 9005 halogen at about 1,700 lumens, so the Sylvania LED’s range is in the same ballpark on paper. LED and halogen lumen ratings aren’t measured the same way, so the numbers don’t predict how the light lands on the road.

Choose by size, not by brand. If you own a 2015–2020 F-150 and want to replace the low beam, you need an H11, which the Sylvania 9005 isn’t.

If you want LED light on the road, a complete assembly designed for it is the compliant route. We list a 2010 Mustang halo projector assembly that ships with H1 bulbs, so it’s a complete assembly rather than an LED kit. See our Spec-D Dual Halo Projector Headlights and the F-150 headlights and Mustang headlights categories.

How to fix flickering LED headlights on an F-150

Flicker and dashboard warnings aren’t always the same problem, so work through it in order.

1. Reseat everything. Check the bulb is locked in and the connector is fully seated.
2. Work out which symptom you have. A dashboard “bulb out” message is a load problem, and flicker or cutting out can come from the power signal. One F-150 owner on a forum reported the error message had nothing to do with the flicker, and that some LED bulbs are sensitive and need a module.
3. Use the harness that came with the kit. The Oracle kit includes CANbus-ready wiring.
4. Add a matching anti-flicker module if needed. Sellers explain that resistors cover warnings but not flicker, capacitors smooth the signal but don’t add load, and full decoders combine both. Even sellers say none is guaranteed. We don’t stock them, so buy the right base (H11, 9005 or H13) elsewhere. One owner reported theirs only worked with the lights in auto mode.
5. Software tweaks are a last resort. Some owners change bulb-out monitoring with diagnostic software such as FORScan. That changes vehicle settings, and we can’t support it.
6. If it still flickers, go back to halogen. These bulbs aren’t certified for the housing, and there’s no guarantee a fix exists for your truck.

Installing and aiming

Install time shoulbe be about 30-45 minutes on the Mustang and 45-60 minutes on the F-150, which needs the wheel liner pushed back to reach the rear access panels on 2015+ trucks

The one tip that matters: orient the LED chips at 3 and 9 o’clock inside the housing. At 12 and 6 the beam scatters. Follow the kit’s instructions, then check the beam on a wall and re-aim.

FAQ

Are LED headlight bulbs brighter than halogen?
Not automatically. Lumen ratings aren’t measured the same way, and beam shape and the housing matter more than the number on the box. Testers on a Tacoma forum found a good halogen upgrade in a halogen housing could outperform LEDs there.

Can I put LED bulbs in projector headlights?
Projector housings built for halogen have the same problem. One repair site argues a retrofit LED bulb can’t produce the proper pattern in a housing designed for halogen, and that applies to projectors, too.