Audi Q5 tail light assemblies utilize 3 distinct bulb sizes: 921, 7506, and P21W, with the lower and main tail light positions requiring 921 or 7506 bulbs and the upper tail light position requiring P21W bulbs. The replacement chart covers vehicle production years spanning 2009 to 2024 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 921 bulb is the most frequently specified size across the Audi Q5 tail light data, appearing in both the Lower Tail Light and Upper Tail Light positions across multiple model years.
The 921 is an ANSI-standard wedge bulb of the T15 type, rated at 12 volts and 16 watts, and is the format commonly used in North American vehicle markets.
The P21W follows the ECE standard used in European and worldwide markets. It is a single-filament signalling bulb with a BA15s bayonet base, rated at 12 volts and 21 watts, drawing slightly more power than the 921.
The BA15s bayonet base of the P21W and the wedge base of the 921 are physically incompatible mounting types, meaning the two bulbs are not interchangeable despite both operating at 12 volts.
The Audi Q5 Upper Tail Light is specified with the P21W for model years 2009-2017, with the 2017 entry carrying a VIN restriction to vehicles up to FP-H-150 000.
The Lower Tail Light on the Audi Q5 uses the 921 across model years 2009-2020 and 2023-2024, with the 2017 entry similarly restricted to VINs up to FP-H-150 000.
The 2019 Lower Tail Light entry for the Audi Q5 carries a "Bumper" position note, indicating the 921 bulb in that year is specific to a bumper-mounted lamp rather than the main tail light assembly.
For model years 2009-2012, the Lower Tail Light position lists both the 921 and the 7506 as separate entries, indicating fitment variations exist within those years requiring attention to the correct application before installation.
The 7506 and 921 bulbs share the same T15 wedge form factor and are often considered functionally equivalent, though the 7506 is rated at 21 watts versus the 921 at 16 watts, which represents a meaningful difference in output and electrical load.
The VIN cutoff notation "To VIN FP-H-150 000" on the 2017 model year entries for both the Lower and Upper Tail Light positions signals a mid-production change, meaning vehicles above that VIN threshold follow a different bulb specification.