White/GMC WHEB Back Up Light Bulb Size

The White/GMC WHEB back up light requires a 1156 bulb size for proper installation and function within the rear lighting assembly. Available data covers the specific range from 1991 to 1995 for the listed 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
1991-1995	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The White/GMC WHEB uses the 1156 bulb for the back up light across the 1991-1995 model years.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical specifications are governed by a recognized North American standard shared across the United States and Canada.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is consistent with standard automotive incandescent back up light applications.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light simultaneously.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width, a common base type in automotive lighting.
The BA15s base requires a rotational lock to seat the bulb, distinguishing it from screw-base or wedge-base alternatives that are not interchangeable with this socket type.