Ford Aerostar Seat Belt Warning Bulb Size

The Ford Aerostar seat belt warning light utilizes 37 and 194 bulb sizes for the internal illumination components. Data for the specific lighting requirements spans from 1986 through 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
1997	194	W5W	Check Price
1996	37	37	Check Price
1994-1995	194	W5W	Check Price
1993	37 (With Digital Inst. Cluster)	37	Check Price
1993	194 (Without Digital Inst. Cluster)	W5W	Check Price
1986-1992	37	37	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with W2.1x9.5d wedge base. 12V, 5W.	W5W	Check Price
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 1W.	37	Check Price

Other Locations

Additional Notes

The bulb 37 is an ANSI-standard miniature wedge type with a T5 form factor, rated at 12 volts and 1 watt, and it serves as the seat belt warning bulb across the Ford Aerostar for model years 1986-1992.
The bulb 194 is an ANSI-standard miniature wedge type with a T10 form factor, rated at 12 volts and 3.78 watts, representing a physically larger and higher-wattage alternative to the 37.
Both bulb types conform to ANSI standards applicable in the United States and Canada, meaning either is subject to standardized dimensional and electrical tolerances within those markets.
The T5 and T10 designations refer to the outer envelope width in units of one-eighth of an inch, making the T10 (194) noticeably wider than the T5 (37). These two bulbs are not interchangeable due to differing physical sizes and wattage ratings.
For the 1993 Ford Aerostar, the correct seat belt warning bulb depends on instrument cluster configuration. Vehicles equipped with a Digital Instrument Cluster require the 37, while those without it require the 194.
The 1996 Aerostar uses the 37 bulb, while the 1994, 1995, and 1997 model years use the 194, indicating that the two bulb types alternate across certain years and are not universally substitutable across the model range.