The Mercedes-Benz GLA45 AMG outer tail light uses a 921 bulb size for replacement applications. The chart covers vehicle production years spanning 2015 to 2019 with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 921 bulb is the sole bulb type listed across all outer tail light positions for the Mercedes-Benz GLA45 AMG spanning 2015-2019.
The 921 bulb follows the ANSI standard, which is the recognized classification system used in the United States and Canada for automotive lighting components.
It is a wedge-base bulb, designated T15, meaning it uses a plastic wedge at its base rather than a metal pin or bayonet fitting for socket retention.
The T15 designation refers to the bulb's tubular envelope, with the numeric portion indicating its width in eighths of an inch.
The 921 operates at 12 volts, consistent with the standard electrical system voltage found in conventional passenger vehicles.
Its rated wattage of 16W places it in a moderate output range typical of backup and tail light applications.
The consistent use of the 921 across the full 2015-2019 model range indicates that the outer tail light socket specification remained unchanged throughout that production period.
Wedge-base bulbs such as the T15 are not interchangeable with bayonet-base or pin-base bulb types, even when voltage and wattage ratings are otherwise similar.