GMC F370 Dome Light Bulb Size

The GMC F370 dome light requires a bulb size of 94 for the interior lighting system. Data for the specified vehicle covers the range from 1956 to 1957.

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
1956-1957	94

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.	94

Other Locations

Additional Notes

The GMC F370 uses the 94 bulb for its dome light across the 1956-1957 model years.
The 94 bulb follows the ANSI standard, meaning it conforms to specifications recognized across the United States and Canada.
This bulb type features a dual-filament design, which allows it to operate at two distinct wattage levels within a single unit.
The 94 uses a BAY15d bayonet base, a two-pin mount where the pins are offset at different heights to ensure the bulb is inserted in the correct orientation.
The 94 is a variant of the 1157 bulb, indicating a close relationship in design and electrical characteristics between the two types.
The bulb operates at 12 volts with a power rating of 21/5 watts, corresponding to its high and low filament outputs respectively.