Ford Aerostar Back Up Light Bulb Size

The Ford Aerostar back up light utilizes bulb sizes 2356, 2456, and 1156 depending on the specific version of the vehicle. Data for the bulb sizes covers the range from 1986 to 1997.

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

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
1996-1997	2356	2356	Check Price
1993-1995	2456	2456	Check Price
1992	2356	2356	Check Price
1991	2456	2456	Check Price
1990	2356	2356	Check Price
1989	2456	2456	Check Price
1988	2356	2356	Check Price
1986-1987	1156	P21W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V.	2356	Check Price
ANSI standard (US & Canada). Festoon bulb, specialty application. 12V.	2456	Check Price
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W	Check Price

Other Locations

Additional Notes

The Ford Aerostar backup light specifications span the 1986-1997 model years and reference three distinct bulb types: 1156, 2356, and 2456.
The 1156 is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base. It appears in the 1986-1987 Ford Aerostar backup light position.
The 2356 is a dual-filament bulb operating at 12V and uses a BAY15d bayonet base. The BAY15d base differs from the BA15s in that its two mounting pins are offset at different heights, making it physically incompatible with BA15s sockets.
The 2456 is a festoon-type bulb rated at 12V, intended for specialty applications. Festoon bulbs are cylindrical in form and mount by contact pressure at each end rather than by a bayonet base, making them mechanically distinct from the 1156 and 2356.
Because the 1156 uses a BA15s base and the 2356 uses a BAY15d base, these two bulbs are not interchangeable despite both being single-contact and double-contact bayonet types respectively. Substituting one for the other risks improper seating or electrical contact failure.
The 2456 festoon type is likewise not interchangeable with either the 1156 or the 2356, as its mounting method and physical form are fundamentally different from bayonet-base bulbs.
All three bulb types listed carry ANSI standard designations valid for both the United States and Canada, indicating conformance to a shared North American specification framework.
The backup light position on the Aerostar used the 2456 festoon bulb across 1989, 1991, and 1993-1995, while the 2356 dual-filament bayonet bulb was specified for 1988, 1990, 1992, 1996, and 1997.