The Mercedes-Benz SL500 front turn signal requires 1156NA, 2357NA, or P21/5W bulb sizes, while the rear turn signal uses P21W bulb size. The replacement chart covers 1994 to 2006 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz SL500 front turn signal uses one of three bulb types across its model years, while the rear turn signal uses the P21W across all listed years from 1994 to 2006.
The 1156NA is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base and natural amber glass. It serves as the front turn signal bulb on the SL500 for model years 2003-2006.
The 2357NA is an ANSI-standard dual-filament bulb rated at 12V with a high filament draw of 26.9W and a low filament draw of 8W. It uses a BAY15d bayonet base with natural amber glass and is specified for the front turn signal on model years 1996-2002.
The BAY15d base used by the 2357NA has offset locating pins, which prevents it from being interchanged with BA15s-based bulbs such as the 1156NA, despite both being bayonet-style bases.
The P21/5W is an ECE-standard dual-filament bulb rated at 12V with filament ratings of 21W and 5W. It also uses a BAY15d bayonet base and is specified for the front turn signal on the 1994-1995 SL500.
Although the 2357NA and P21/5W share the same BAY15d base type, they follow different standards, ANSI and ECE respectively, and carry different wattage ratings, which makes them non-equivalent replacements despite their physical base compatibility.
The P21W is an ECE-standard single-filament bulb rated at 12V and 21W with a BA15s bayonet base. Its consistent use across all listed rear turn signal positions from 1994 to 2006 reflects a stable rear lighting specification throughout the SL500's production run in those years.
The 1156NA and P21W share the same BA15s base type and both operate at 12V and 21W, but they originate from different standards, ANSI and ECE respectively. Physical fitment may be possible in some cases, though the specifications list them as distinct part numbers for their respective positions.
The front turn signal specification for the SL500 shifted from the ECE-standard P21/5W in 1994-1995 to the ANSI-standard 2357NA in 1996, and then to the ANSI-standard 1156NA in 2003, representing a change from dual-filament to single-filament use in the front position.
Natural amber glass, as noted on both the 1156NA and 2357NA, produces an amber signal output directly from the bulb itself, as opposed to clear bulbs that rely on a colored lens to produce the required amber turn signal color.