Upgrading to LED Headlight Bulbs

Video: How to install the LED headlight H4 correctly? (YouTube)

An LED replacement bulb may change light output, color, power draw, and beam pattern, but results depend on the bulb, headlamp housing, vehicle electronics, and installation. Confirm bulb size, physical clearance, connector type, electrical compatibility, and road-use requirements before purchase.

1. Find your bulb size

Headlights use standardised bases — H11, H4, 9005/HB3, 9006/HB4, H7 and so on, with low beam and high beam often different sizes. Check your owner’s manual, the printing on your current bulb, or a bulb-finder chart for your exact year/model before ordering. A vehicle name in a listing is a compatibility reference, not a guarantee; compare the listed bulb size, connector, dimensions, and included parts with the vehicle before ordering.

2. Install

1. Work with the engine off. Access the back of the headlight (some cars hide it behind a dust cap or the wheel-arch liner).
2. Twist the old bulb counter-clockwise and unplug it. Don’t touch the glass of any halogen you plan to keep as a spare.
3. Seat the LED so its diodes face side-to-side (3 and 9 o’clock), mimicking a halogen filament — this is what keeps the beam pattern correct.
4. Plug in, refit the dust cap (larger LED bodies may need the supplied extended cap), and test low/high beam.

3. Aim the beam — don’t skip this

Park facing a wall about 25 ft away, mark the height of the headlight centres, and adjust each light’s screw so the beam cutoff sits slightly below the mark and kicks up to the right. Properly aimed LEDs light the road, not oncoming windshields — misaimed ones are what give LED upgrades a bad name.

Flicker and warnings (CANbus)

Some vehicles pulse-check their bulbs and will flicker an LED or throw a “bulb out” warning. When supported, a compatible decoder or resistor module may help with flicker or bulb warnings, but results vary by vehicle.

Road-use requirements

Fitment does not by itself establish that an LED replacement is approved for on-road use in a particular housing or location. Check the product markings and applicable federal, state, and local requirements before road use. Ensure the beam is correctly aimed and does not create glare.

Tips

• Replace bulbs in pairs — mismatched colour looks worse than the old halogens.
• Fan-cooled LEDs need airflow; don’t wrap the body in the dust boot.