Ford Aerostar Automatic Transmission Indicator Bulb Size

The Ford Aerostar automatic transmission indicator utilizes bulb size 194 and bulb size 37 for illumination. Available data covers the specific range from 1987 through 1997 for the listed components.

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
1990-1997	194
1988	194
1987	37

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 1W.	37

Other Locations

Additional Notes

The Ford Aerostar automatic transmission indicator uses two distinct bulb sizes across its production years: the 194 and the 37, both of which are ANSI-standard miniature wedge bulbs rated for 12 volts.
The 194 bulb is a T10 miniature wedge type rated at 3.78 watts, and it serves as the automatic transmission indicator bulb for the 1988-1997 Ford Aerostar, with the exception of the 1987 model year.
The 37 bulb is a T5 miniature wedge type rated at 1 watt, and it is specified exclusively for the 1987 Ford Aerostar automatic transmission indicator position.
The T10 and T5 designations refer to the width of the wedge base, with T10 being physically larger than T5. These two bulb types are not interchangeable due to their differing base sizes and wattage ratings.
The wattage difference between the two bulbs is notable: the 194 (T10) draws 3.78 watts while the 37 (T5) draws only 1 watt, meaning the two types produce different levels of illumination and place different electrical loads on the circuit.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized physical and electrical specifications recognized across those markets.