In most cars, license plate lights use a small wedge or festoon bulb—most often a 194/168 wedge—or a 31mm festoon. Many newer vehicles use LED modules that aren’t replaceable as a single bulb. Check your owner’s manual or inspect the housing to know the exact part, since it’s also a legal requirement in many places that license plates be illuminated at night.
Common license plate bulb types
These are the main categories you’ll encounter when shopping for a replacement. The right choice depends on the socket and housing in your car.
Halogen wedge and festoon bulbs
- Wedge-base bulbs (commonly labeled 194 or 168; also sold as T10 wedges). These push into a wedge socket and are widely used in many older and mid-range vehicles.
- Festoon bulbs (cylindrical with contacts at each end); common lengths include around 31mm or 36mm, used in some license plate housings.
Halogen wedge and festoon bulbs cover a large share of installed license plate lamps, making them the most straightforward option to replace on many cars.
LED license plate modules
Many newer vehicles use LED assemblies or replaceable LED bulbs designed to fit the same socket style as halogen equivalents. In some cases, you may need to replace the entire light housing rather than a single bulb.
How to identify the exact bulb for your vehicle
To determine the precise bulb type before buying a replacement, follow these checks.
- Consult the vehicle’s owner’s manual or service data for the license plate light size and base type.
- Remove the current bulb to inspect its base shape (wedge, festoon, or LED module) and any size markings.
- Note the diameter, length, and connector style, and compare with catalogs or retailer listings by make/model/year.
- Check online parts databases or contact the dealership parts department if you’re unsure, using your car’s exact year, make, and model.
- If you’re switching to LEDs, ensure the replacement is CAN-bus compatible (to avoid dimming or error codes) and that it fits the housing without modification.
Correctly identifying the base type helps avoid buying the wrong part and speeds up the replacement process.
How to replace safely
These steps outline a typical replacement path for a traditional halogen or LED-compatible bulb. Procedures can vary by vehicle, so consult the manual if needed.
- Turn off the vehicle and remove the keys; for extra safety, disconnect the negative battery terminal.
- Access the license plate light housing by removing the license plate or accessing the rear of the lamp assembly as required.
- Detach the old bulb: wedge bulbs pull straight out or twist; festoon bulbs replace by removing the old module ends; LED modules may require unplugging a connector or twisting a housing.
- Install the replacement bulb or module in the correct orientation; avoid touching halogen bulbs with bare fingers, as oils can shorten life.
- Test the light by reassembling the housing and turning on the lights; verify brightness and proper alignment.
If the light doesn’t come on after replacement, re-check the fuse, wiring, and connectors, and ensure the LED replacement is compatible with your vehicle’s electrical system.
Summary
License plate bulb choices vary by model. The most common options are halogen wedge bulbs (like 194/168) and festoon bulbs, with LED modules becoming increasingly prevalent in newer cars. Always verify by checking the manual or inspecting the socket, and consider LED replacements for longer life and brightness when compatible. If you’re unsure, a quick parts lookup by make/model/year or a visit to an auto parts store can ensure you get the right part the first time.