Giant C116 Back Up Light Bulb Size

The Giant C116 back up light utilizes P21W and 199 bulb sizes for the rear illumination system. Available data for the specified vehicle covers the period from 1984 through 1989.

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
1989	P21W
1988	199
1984-1987	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	199

Other Locations

Additional Notes

The P21W and 199 bulbs are the two back up light bulb types specified for the Giant C116 across its listed model years.
Both bulb types operate at 12V and 21W, and both use a single filament, making them functionally equivalent in terms of power draw and light output.
Both the P21W and the 199 share a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar.
The P21W follows the ECE standard, which governs lighting equipment regulations in Europe and much of the wider world.
The 199 follows the ANSI standard, which applies to the United States and Canada, and is classified as a variant of the 1156 bulb type.
The Giant C116 (1984-1987 and 1989) uses the P21W, while the 1988 model year uses the 199.
Because the P21W and 199 share the same BA15s base and identical electrical ratings, physical fitment between the two is generally considered interchangeable, though regional certification standards differ.