Saab 9-5 Back Up Light Bulb Size

The Saab 9-5 back up light utilizes H21W and P21W bulb sizes for the lighting components. Available data covers the range from 1999 through 2011 for the specified vehicle.

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
2010-2011	H21W
1999-2009	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 Saab 9-5 back up light specifications cover model years 1999 through 2011 and reference two distinct bulb types: the P21W and the H21W.
The P21W is an ECE-standard single-filament signalling bulb rated at 12 volts and 21 watts, fitted with a BA15s bayonet base.
The H21W is also an ECE-standard single-filament signalling bulb rated at 12 volts and 21 watts, but it uses a BAY9s base rather than a BA15s base.
The BA15s base found on the P21W is a single-contact bayonet fitting with a 15mm collar, while the BAY9s base on the H21W is an offset-pin bayonet fitting with a 9mm collar, making the two bulbs physically incompatible with each other despite sharing the same wattage rating.
The Saab 9-5 used the P21W for model years 1999-2009, representing the majority of the production span covered by these specifications.
The H21W fitment applies to the 2010-2011 model years, indicating a base type change in the back up light housing during that period.
Because the P21W and H21W use different base configurations, a bulb from the 1999-2009 fitment group is not a direct replacement for a 2010-2011 vehicle, and vice versa.
Both bulb types operate on a standard 12-volt automotive electrical system and consume 21 watts, which is a common output level for single-filament signalling applications such as reverse lights.