The Volvo S70 front inner turn signal requires a 3457NA or 3357NA bulb size, while the front turn signal uses a 3357NA bulb and the rear turn signal uses a PY21W bulb size. The replacement chart covers 1998 to 2000 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 Volvo S70 turn signal system draws from two different standardization frameworks across its positions. The front positions use ANSI-standard bulbs, while the rear turn signal uses an ECE-standard bulb, reflecting a mixed regulatory design common in vehicles sold across multiple markets.
The PY21W is the specified rear turn signal bulb for the Volvo S70 across all listed model years (1998-2000). It operates on the ECE standard, which is the regulatory framework used in Europe and most international markets outside North America.
The PY21W uses a BAU15s bayonet base, which is an offset single-contact base. The offset pin arrangement is intentional, as it prevents accidental installation of non-amber bulbs in positions where amber color is required by ECE regulations.
The PY21W produces its amber color through a tinted glass envelope rather than a clear bulb in an amber housing. It runs at 12V and 21W as a single-filament type, meaning it serves only one lighting function per socket.
The 3357NA is the specified front turn signal bulb across all listed model years (1998-2000) and also serves as the front inner turn signal for 1998. The NA suffix designates natural amber glass, meaning the amber color comes from the glass itself rather than from a painted or coated surface.
The 3457NA replaces the 3357NA in the front inner turn signal position for the 1999-2000 model years. The key distinction between the two is filament count: the 3357NA is a single-filament bulb rated at 27W, while the 3457NA is a dual-filament bulb rated at 27W and 7W, allowing it to serve two separate lighting functions from a single socket.
Because the 3357NA and 3457NA share the same T25 wedge base and physical form, they are physically interchangeable in the socket. However, substituting a single-filament 3357NA into a position specified for the dual-filament 3457NA would result in the loss of the secondary 7W filament function.
The T25 designation shared by both the 3357NA and 3457NA refers to the wedge base size, which is a push-in style base without a separate locking mechanism. This base type is widely used in automotive signal and parking light applications.
The front inner turn signal position on the Volvo S70 is the only position in these specifications where the bulb type changes across model years, shifting from the 3357NA in 1998 to the 3457NA in 1999-2000. All other positions retain the same bulb type throughout the listed range.
The 3457NA and PY21W are not interchangeable despite both being amber single- or dual-filament bulbs. They differ in base type, wattage, and regulatory standard, making cross-position substitution between front inner and rear sockets incompatible on the Volvo S70.