Chevrolet Biscayne High Beam Indicator Bulb Size

Additional Notes

• The 194 bulb is a T10 miniature wedge type operating at 12V and 3.78W under the ANSI standard. It serves as the high beam indicator bulb in the Chevrolet Biscayne for the 1969-1970 and 1972 model years.
• The 1895 bulb is a T5 miniature wedge type rated at 12V and 0.9W. At 0.9W, it draws notably less power than the 194 bulb and fits the 1964-1965 and 1971 model years.
• Although both the 194 and 1895 bulbs share a wedge base construction and 12V rating, their physical sizes differ. The T10 and T5 designations refer to the tube width in eighths of an inch, making these two bulb types non-interchangeable despite their similar base style.
• The 53 bulb is a single-filament type with a BA9s base, rated at 12V and 2W. It is specified for the 1958-1960 Chevrolet Biscayne high beam indicator.
• The 57 bulb also uses a BA9s base and operates at 12V, but is rated at 1W rather than the 2W of the 53. These two bulbs share the same base type yet differ in wattage, which affects their suitability as substitutes for one another.
• The 257 bulb is listed as either a festoon or BA9s base instrument bulb, rated at 12V and 2W. This dual-base designation indicates it was available in more than one physical configuration, a factor relevant to fitment in the 1961 and 1963 model years.
• All five bulb types across these specifications conform to ANSI standards applicable in both the United States and Canada, indicating a shared regulatory framework for their electrical and physical ratings.
• The high beam indicator position in the Biscayne used four distinct bulb types across the 1958-1972 production span, with no single bulb type serving the full range of model years, which has direct implications for parts interchangeability across those years.