Jaguar Vanden Plas front inner turn signal bulbs use PY21W or 12496 size, while front outer and rear turn signal bulbs utilize PY21W, 12496, or P21W sizes. The replacement chart covers 1982 to 2009 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 PY21W is the most frequently specified bulb across the Jaguar Vanden Plas turn signal positions. It is an ECE-standard single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s offset bayonet base. The amber coloring is built into the glass envelope rather than applied as a coating.
The P21/5W is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament. It uses a BAY15d bayonet base, which has two pins set at different heights to prevent incorrect installation. This base configuration is physically distinct from those used by the PY21W and P21W, making cross-substitution impossible without a socket adapter.
The P21W shares the same 12V, 21W single-filament rating as the PY21W but uses a BA15s bayonet base with two pins at equal heights. Its glass envelope is clear rather than amber. The BA15s base is not interchangeable with the BAU15s base of the PY21W, as the pin offset on the BAU15s is a deliberate anti-substitution feature.
The 12496 is a Philips and Osram part number designation for a 12V halogen bulb intended for specialty applications. Unlike the ECE-coded bulbs in these specifications, the 12496 is identified by a manufacturer part number rather than a standardized type code.
The Jaguar Vanden Plas front turn signal position used the P21/5W dual-filament bulb from 1982-1994. From 1995 onward, that position transitioned to single-filament types, with P21W specified for 1995-2000 and alternating PY21W and 12496 designations appearing in later years.
The rear turn signal position on the Vanden Plas used the P21W single-filament bulb from 1982-1993, then shifted to PY21W and 12496 designations for subsequent model years. The rear and front turn signal positions do not always share the same bulb type within a given model year.
For the 2004-2006 model years, the Vanden Plas carries two distinct front turn signal positions: a Front Outer Turn Signal specifying PY21W and a Front Turn Signal specifying 12496. These are separate sockets requiring different bulbs, and the designations are not interchangeable between the two positions.
The 2008 Front Inner Turn Signal specifies the 12496, while the 2007 and 2009 model years for that same position specify the PY21W. A technician sourcing a replacement for the 2008 model year would require a different bulb than one servicing the adjacent model years.
The BAU15s base of the PY21W, the BA15s base of the P21W, and the BAY15d base of the P21/5W are three mechanically distinct bayonet configurations. Despite the similar wattage ratings shared by these bulb types, their base designs prevent direct physical substitution across socket types.
Across all listed positions and model years, the Jaguar Vanden Plas turn signal specifications reference only three ECE-coded bulb types and one manufacturer-coded type. The ECE designations follow a standardized naming convention in which the letter prefix indicates filament count and glass color, while the numerical suffix indicates wattage.