Volvo S60 Turn Signal Bulb Size

Additional Notes

• PY21W is the most frequently specified bulb across the Volvo S60 turn signal positions. It follows the ECE standard used in Europe and worldwide markets, operates at 12V and 21W, uses a single filament, and fits a BAU15s bayonet base. The offset pins of the BAU15s base distinguish it physically from other bayonet types, preventing incorrect installation.
• The 1157NA and 1034NA bulbs both follow the ANSI standard common to US and Canadian markets. Both use a BAY15d bayonet base with dual filaments and natural amber glass, rated at 12V with a 21W/5W filament output. The 1034NA is a variant of the 1157 type, meaning the two share the same base and general construction but differ in filament wattage ratings.
• The BAU15s base of the PY21W and the BAY15d base of the 1157NA and 1034NA are not interchangeable. The pin offset on the BAU15s is asymmetric at 150 degrees, while the BAY15d uses a straight dual-pin arrangement. Substituting one for the other is not possible without a socket adapter.
• The front turn signal of the Volvo S60 shows a split between PY21W and ANSI-type bulbs across model years. The 2009 model year uses PY21W, while 2008 uses 1157NA, and 2005 uses 1157NA for vehicles built from chassis 425000 onward. This indicates that the applicable bulb type for certain years is tied to a specific chassis number threshold rather than the model year alone.
• For the 2006 and 2007 front turn signal positions, the specification notes "With Socket, From Chassis 425000," indicating the PY21W fitment applies only to vehicles at or above that chassis number. Vehicles below that threshold are not covered by this specification entry.
• The front turn signal for model years 2014-2018 uses the 12174SV, a Philips SilverVision halogen bulb with an enhanced coating. This is a manufacturer-specific part number rather than a universal ANSI or ECE designation, which means cross-referencing to a generic equivalent requires confirming the base type and wattage separately.
• The rear turn signal alternates between PY21W and the Philips/Osram 12496 across multiple model years. For example, the 2016 rear turn signal uses 12496 while the 2015 and 2017 positions use PY21W. These two bulb types are not confirmed as interchangeable within these specifications, and the alternating pattern reflects distinct fitment requirements per year.
• The 12496 is identified as a specialty halogen bulb rated at 12V under the Philips and Osram part numbering systems. It appears in the rear turn signal position for the 2006, 2007, 2009, 2012, 2014, and 2016 model years. Because it carries a proprietary part number rather than an ANSI or ECE designation, direct substitution with a generic bulb type warrants verification of the base type and wattage.
• The front inner turn signal position is specified only for model years 2005-2009, all of which use PY21W. This position is separate from the general front turn signal, and the two positions do not necessarily share the same bulb type across overlapping model years.
• The dual-filament construction of the 1157NA and 1034NA means these bulbs serve two electrical circuits within a single housing, typically combining a higher-wattage turn signal filament with a lower-wattage running or parking light filament. Installing a single-filament bulb such as PY21W in a socket designed for a dual-filament type would result in one circuit receiving no illumination.