The brake light configuration on the 2018 Hyundai Elantra depends on trim and market: most models with bulbs use a 3157 dual-filament bulb for the rear brake/taillight, while higher trims or specific markets switch to LED tail lights that don’t use replaceable bulbs.
Understanding the two lighting options on the 2018 Elantra
Hyundai offered both incandescent and LED tail lighting on the Elantra in 2018, so the “brake light” you replace could be a bulb or an LED module. The exact setup is determined by the trim level and the regional specifications.
Incandescent bulb option (most common on base trims)
For models with traditional bulbs, the rear brake/taillight typically uses a dual-filament bulb, most commonly the 3157 type. This allows one filament for the tail light and a brighter filament for the brake function. Some markets may use a different dual-filament variant such as 3157K for amber turn signals, but the brake/taillight function generally uses the same 3157 family.
Before listing common variants, here is the typical bulb configuration you may encounter in incandescent Elantras.
- Rear brake/taillight bulb: 3157 dual-filament (bulb-based) in the relevant lamp housing.
- Turn signal bulb (if separate): common variants include 3156 or 3157 depending on the socket configuration in the same cluster.
In summary, if your Elantra uses bulbs, you’ll primarily deal with a 3157-style rear brake/taillight bulb, with the exact socket depending on the trim.
LED tail lights option (trims/markets)
Some 2018 Elantras use LED rear tail lights, where the brake and tail functions are provided by LED modules rather than replaceable bulbs. In these cases, there is no bulb to replace in the tail light assembly; failures are addressed by replacing the LED module or the entire tail light assembly through Hyundai or a supplier.
Noting that LED tail lights became more common on higher trim levels or specific markets, it’s essential to verify which system your vehicle has to know the replacement approach.
- Brake/taillight: LED modules (no replaceable bulb).
- Replacement approach: tail-light assembly or module replacement rather than bulb replacement.
In short, if your Elantra is LED-equipped, you’ll replace the LED unit, not a bulb. If it uses bulbs, you’ll use a 3157 dual-filament bulb in the brake/taillight.
How to confirm the exact type on your vehicle
To determine which configuration your 2018 Elantra has, inspect the rear lighting in daylight and when the lights are on, consult the owner’s manual or check the bulb socket, and compare with the LED modules visible in the tail light cluster.
- Inspect the tail light housing: presence of LED chips or a solid bulb socket is a quick indicator.
- Check the owner's manual or Hyundai's official parts diagram for your specific trim/year.
- Physically access the bulb (if possible) to confirm whether it’s a filament bulb (incandescent) or an LED module.
With the correct identification, you can purchase the appropriate replacement—3157 dual-filament bulbs for incandescent setups or an LED replacement/assembly for LED setups.
Summary
The 2018 Hyundai Elantra may use either a 3157 dual-filament bulb for incandescent brake/taillights or LED tail lights on higher trims or specific markets. Always verify your exact trim and region to determine whether you should replace a bulb or the entire LED module.