Ford Escort Dome Light Bulb Size

The Ford Escort dome light uses bulb sizes DE3175, 578, 1816, 906, and 1003 depending on the specific version of the vehicle. Available data covers the range from 1956 to 2003 for the components listed in the provided specifications.

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
1998-2003	DE3175
1997	578
1991-1993	DE3175
1988-1990	1816
1981-1987	906
1956-1957	1003

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, 31mm length, end-cap contacts. 12V.	DE3175
ANSI standard (US & Canada). Festoon bulb, 41mm length, end-cap contacts. 12V, 12W.	578
ANSI standard (US & Canada). Miniature wedge bulb (T3.25). 12V, 4W.	1816
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 8W.	906
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1003

Other Locations

Additional Notes

The DE3175 is the most frequently specified dome light bulb across the Ford Escort's model history, covering the 1991-1993 and 1998-2003 model years. It is a festoon-type bulb measuring 31mm in length with end-cap contacts, rated at 12V, and manufactured to ANSI standards for the US and Canadian markets.
The 906 bulb is the second most recurring specification, fitted to the Ford Escort across the 1981-1987 model years. It is a miniature wedge bulb of the T10 type, rated at 12V and 8W, and also conforms to ANSI standards.
Festoon bulbs use end-cap contacts at each end of a cylindrical housing, and physical length is the primary factor in fitment. The DE3175 and the 578 are both festoon types, but they differ in length, at 31mm and 41mm respectively, making them non-interchangeable despite sharing the same contact style.
The 578 festoon bulb is specified solely for the 1997 Ford Escort dome light. At 41mm and 12W, it is longer and draws more power than the DE3175 used in surrounding model years, which means substituting one for the other would result in an incorrect physical fit.
The 1816 is a miniature wedge bulb of the T3.25 type, rated at 12V and 4W, and is specified for the 1988-1990 model years. Wedge bulbs rely on the base being pinched into the socket rather than using a bayonet or screw mechanism, and the T3.25 designation refers to the bulb's tubular envelope size.
The 1003 bulb carries a BA15s bayonet base, which is a single-contact bayonet fitting. This base type is mechanically distinct from both wedge and festoon mounting styles, meaning it is not interchangeable with any of the other bulb types listed in these specifications.
The 1003 is rated at 12V and 21W, the highest wattage among all bulb types listed in these specifications. It is assigned to the 1956-1957 Ford Escort model years.
The 906 T10 wedge and the 1816 T3.25 wedge share the same general wedge-base mounting principle but differ in envelope size and wattage, at 8W and 4W respectively. These differences make them non-interchangeable in practice despite the similar base style.
All five bulb types in these specifications are rated at 12V and conform to ANSI standards applicable in both the United States and Canada, indicating a consistent operating voltage across the full range of listed model years.
Four distinct bulb base technologies are represented across the Ford Escort dome light specifications: the festoon end-cap, the T3.25 miniature wedge, the T10 miniature wedge, and the BA15s single-contact bayonet. Each requires a physically different socket, and no cross-type substitution is supported by the listed fitments.