Eagle Summit Back Up Light Bulb Size

The Eagle Summit back up light uses 1156 and P21W bulb sizes according to the provided data. The information covers the range from 1989 through 1992 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
1989-1992	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 Eagle Summit uses the 1156 bulb across its 1989-1992 model years for the back up light position.
The 1156 is an ANSI-standardized bulb type recognized in both the United States and Canada.
It operates on a 12-volt electrical system and draws 21 watts, which is typical for single-filament automotive signal and reverse light applications.
The 1156 uses a BA15s bayonet base, a single-contact mount where the "s" denotes a single pin, distinguishing it from the dual-pin BA15d variant.
Because the 1156 is a single-filament bulb, it serves only one lighting function per socket, which is consistent with its use in a dedicated back up light position.
The BA15s base is not interchangeable with dual-contact bayonet bases, so substituting a physically similar bulb with a BA15d base would result in an improper fit.