Volvo XC90 Back Up Light Bulb Size

The Volvo XC90 back up light utilizes H21W and P21W bulb sizes for illumination across various production periods. Available data covers a range from 2003 through 2024 for the specified vehicle components.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2023-2024	H21W
2021	H21W
2003-2014	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BAY9s base. 12V, 21W.	H21W
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The P21W bulb is the most frequently specified backup light bulb across the Volvo XC90 model years listed, covering 2003-2014.
The H21W bulb is specified for the 2021-2024 Volvo XC90 backup light position, replacing the P21W used in earlier model years.
Both the P21W and H21W operate at 12 volts and 21 watts, and both are single-filament signalling bulbs built to the ECE standard used in Europe and worldwide markets.
Although the two bulb types share identical voltage and wattage ratings, they are not interchangeable due to different base configurations.
The P21W uses a BA15s single-contact bayonet base, which features a single pin on the side of the metal cap for locking into the socket.
The H21W uses a BAY9s base, which is an offset-pin bayonet fitting designed to prevent incorrect installation by ensuring the bulb can only be seated in one orientation.
The differing base types between the H21W and P21W mean that a bulb from one group cannot be physically inserted into a socket designed for the other, making cross-substitution mechanically impossible without modification.