BMW Z3 Back Up Light Bulb Size

The BMW Z3 back up light requires a P21W bulb size for the rear lighting assembly. Available data for the bulb specifications covers the period from 1996 to 1998.

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
1996-1998	P21W

Bulb Specifications

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

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Additional Notes

The BMW Z3 uses the P21W bulb for the back up light across the 1996-1998 model years.
The P21W is an ECE-standardized bulb type, meaning it conforms to European and international regulations for automotive lighting.
P21W bulbs operate on a 12-volt electrical system and draw 21 watts, which is typical for single-filament signalling applications such as reverse lights.
The P21W uses a BA15s bayonet base, a single-contact fitting where the "s" denotes a single pin offset to one side of the base.
Because the BA15s base is a single-contact design, it is not interchangeable with the BA15d base, which carries two contacts for dual-filament bulbs.