Mercedes-Benz 600SEL front turn signal bulb uses 1034 size while rear turn signal bulb uses P21W size. The replacement chart covers 1992 to 1993 vehicle production years 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 Mercedes-Benz 600SEL uses two distinct bulb standards across its front and rear turn signal positions, reflecting a split between North American and European lighting specifications within the same vehicle's fitment data.
The 1034 bulb follows the ANSI standard, which governs lighting components sold in the United States and Canada. It operates at 12V with a dual-filament output of 21/5W and uses a BAY15d bayonet base.
The BAY15d base is an offset-pin bayonet mount, meaning its two pins are positioned at different heights along the base. This physical asymmetry prevents incorrect insertion and is a defining characteristic of dual-filament bayonet bulbs.
The 1034 is a variant of the 1157 bulb. While the two share the same BAY15d base and dual-filament design, they are not universally interchangeable, as wattage or base pin offset tolerances may differ depending on the socket specification.
The P21W bulb follows the ECE standard, which applies to European and international markets. It operates at 12V with a single-filament output of 21W and uses a BA15s bayonet base.
The BA15s base is a single-contact bayonet mount with two pins at equal heights. Because it carries only one filament, it is not interchangeable with the BAY15d base used by the 1034, despite both being 15mm bayonet-style fittings.
The front turn signal positions on the 600SEL for model years 1992-1993 specify the 1034 bulb, while the rear turn signal positions for the same years specify the P21W.
The dual-filament nature of the 1034 suggests the front turn signal housing on the 600SEL may serve a combined function, such as pairing turn signal operation with a parking or daytime running light circuit, whereas the single-filament P21W at the rear is dedicated solely to signalling.
Although both the 1034 and P21W share a nominal 21W output on their primary filaments, the differing base types make them physically incompatible with each other's sockets, and substitution between the two positions is not supported by the specifications.
The fitment data covers model years 1992-1993 for both the front and rear turn signal positions of the 600SEL, with no variation in bulb specification between those two years for either position.