Mercedes-Benz CL600 Back Up Light Bulb Size

Additional Notes

• The Mercedes-Benz CL600 backup light specifications cover model years 1998-2010, with two distinct bulb types used across that span.
• The P21W is the more widely used of the two bulb types in these specifications, appearing across eight model years of the CL600.
• The P21W follows the ECE standard, which is a lighting regulation framework used in Europe and internationally, making it a globally recognized bulb designation rather than a manufacturer-specific one.
• The P21W operates at 12 volts with a 21-watt output and uses a BA15s bayonet base, which is a single-contact base with a 15mm collar.
• As a single-filament bulb, the P21W is designed for dedicated signalling functions such as backup lighting, where only one consistent light output level is required.
• The 2007-2010 CL600 uses the 12184 bulb, which is a Philips part number designation for a 12-volt halogen bulb intended for specialty automotive applications.
• Because the 12184 is identified by a manufacturer part number rather than a universal standard, fitment is tied to that specific Philips product rather than a broader bulb category.
• The P21W and 12184 are not listed as interchangeable in these specifications, and the CL600 production years are divided between the two without overlap.