The Mercedes-Benz E430 brake light uses P21/4W and P21W bulb sizes depending on the specific production period for the vehicle. Available data for the lighting components covers the period from 1998 through 2002.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz E430 brake light specifications cover model years 1998-2002, with two distinct bulb types used across that span depending on the year.
The P21/4W is a dual-filament signalling bulb operating at 12V with a 21W main filament and a 4W secondary filament, conforming to ECE standards used in Europe and worldwide. It uses a BAZ15d bayonet base.
The P21W is a single-filament signalling bulb operating at 12V at 21W, also conforming to ECE standards. It uses a BA15s bayonet base.
The BAZ15d and BA15s bayonet bases are physically distinct, meaning P21/4W and P21W bulbs are not interchangeable despite their similar appearance and shared voltage rating.
The Mercedes-Benz E430 uses the P21/4W for the brake light position in model years 2000-2002, while the P21W is specified for 1998-1999.
The dual-filament design of the P21/4W allows a single bulb to serve two lighting functions simultaneously, which is why it is commonly used in combined brake and tail light assemblies.
For the 1998-1999 model years, the Center High Mount Stop Light also uses the P21W, consistent with the brake light specification for those same years.
The Center High Mount Stop Light specification is limited to 1998-1999, while the main brake light position carries specifications through 2002.
Substituting a P21W in a socket designed for the P21/4W would be incorrect, as the BAZ15d base of the P21/4W features offset pins to prevent incorrect installation, a safety measure built into the ECE standard.