LED Replacement Bulbs

What these bulbs replace

LED replacement bulbs swap into the socket of a factory halogen or incandescent bulb. They use diodes and a heat sink or fan rather than a filament, and are sold for headlights, fog lights, turn signals, parking and interior lamps. The sample listings include headlight conversion kits, fog bulbs, amber 7443 signal bulbs and wedge-style T10 bulbs, along with a halogen twin pack and an HID ballast.

Bulb sizes and bases

The most important step is matching the base type.

• Headlight bulbs come in sizes such as H1, H3, H4, H11, 9005 and 9006, and some vehicles use different sizes for low and high beams.
• Fog light bulbs are commonly H8, H10, H11 or H16, depending on the vehicle.
• 7443 and similar bulbs serve as signal and brake lamps, while T10 wedge bulbs serve in marker and interior positions.
• Dual-beam bulbs such as H4 combine low and high functions in one bulb.

Check your owner's manual or look at the bulb itself for the size before shopping.

Things to compare

Color temperature is listed in kelvin, with lower numbers warmer and higher numbers bluer. Cool or white bulbs look crisp but extremely blue light may reduce usable output in rain or fog. Consider amber for signals and check the lens color.

Beam pattern matters most. A reflector or projector housing is designed around a filament position, so an LED that places its diodes differently can scatter light and glare other drivers. Look for products designed to mimic the filament position. Cooling design, such as a fan or heat sink, affects lifespan and whether the bulb fits in the available space behind the housing.

Installation and compatibility

Some vehicles use computer monitoring that expects a certain current draw, so an LED can trigger a bulb-out warning or flicker. CAN-bus decoders or resistors can resolve this on supported vehicles. Turn signals may hyper-flash without a load resistor or an LED-compatible flasher.

Headlight output and color are regulated, and rules vary by state, so verify local requirements. Aim the headlights after changing bulbs, avoid touching the glass of halogen replacements, and test every function. A professional installation may help if the bulb access is tight.

Heat, power and housing considerations

LED bulbs create heat at the base of the diodes, and unlike halogen bulbs they cannot shed it as radiated light. That is why designs use aluminum bodies, copper cores, fans or braided straps. Check how much room is available behind the headlight housing, including the dust cover, because a bulb with a large heat sink or driver can prevent the cover from closing and let moisture in.

• Choose bulbs that mount securely in the retaining ring so the beam stays aimed correctly
• Make sure wiring and drivers are routed away from moving parts and hot engine components
• Replace both bulbs in a pair so color and brightness match
• Confirm the voltage range matches your vehicle's electrical system
• Check the bulb after a few weeks of use for loose connections or moisture

Poor quality conversions cause most complaints: glare, dark spots and short life. Aim the headlights on a wall or with a shop's equipment after installing new bulbs, and observe how oncoming drivers react. If the beam looks scattered or has bright spots above the cutoff, the bulb is not seating correctly or is not suited to your housing, and it should be removed.