The Volvo XC70 brake light uses a P21W bulb size for the rear lighting system. Data for the specific component covers the period from 2003 through 2007.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Volvo XC70 uses the P21W bulb size across both the brake light and center high mount stop light positions for the 2003-2007 model years.
The P21W is an ECE-standardized bulb, meaning it conforms to European and international automotive lighting regulations rather than SAE standards used in North American specifications.
P21W bulbs operate at 12 volts with a 21-watt output, which is a standard wattage for single-filament stop and signal applications.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base, confirming it is a single-filament design.
Because the P21W is single-filament, it serves a dedicated function per socket. The Volvo XC70 therefore uses separate bulb positions for the brake light and the center high mount stop light rather than a dual-filament arrangement.
The BA15s base is not interchangeable with the BA15d base, which carries two contacts for dual-filament bulbs. Substituting a BA15d bulb in a BA15s socket is not a compatible fitment.
The uniform use of P21W across both lighting positions on the Volvo XC70 means a single bulb type serves multiple locations on the vehicle, though each position requires its own individual unit.