Volvo S90 Map Light Bulb Size

The Volvo S90 map light requires bulb size 12961 or H21W depending on the specific version of the vehicle. Data for the bulb sizes covers the range from 1997 to 2020.

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
2020	H21W
1997-1998	12961

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BAY9s base. 12V, 21W.	H21W
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

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Additional Notes

The Volvo S90 map light specifications reference two distinct bulb types across the model's listed years: the H21W and the 12961.
The H21W is an ECE-standard single-filament signalling bulb rated at 12V and 21W, fitted with a BAY9s bayonet base. At 21 watts, it draws considerably more power than a typical map light bulb.
The BAY9s base uses an offset pin arrangement, which prevents accidental installation of incompatible bulbs into the same socket.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W. The wedge base relies on spring tension from the socket rather than a locking pin or bayonet mechanism.
The H21W and the 12961 use physically incompatible bases, the BAY9s and W2.1x9.5d respectively, meaning the two types are not interchangeable with each other.
The 2020 Volvo S90 map light position takes the H21W bulb.
The 1997-1998 Volvo S90 map light position takes the 12961 bulb.
The significant wattage difference between the H21W at 21W and the 12961 at 5W reflects a fundamental difference in bulb design purpose, as the H21W is classified as a signalling bulb rather than a standard illumination bulb.