GMC 370 Turn Signal Bulb Size

GMC 370 front and rear turn signal bulbs utilize 1156, 1073, and 1129 bulb sizes across different model configurations. The replacement chart covers 1951 through 1959 production years with corresponding bulb size specifications.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Front Turn Signal

YearsBulb Size
19591156
1956-19581073
1951-19551129

Rear Turn Signal

YearsBulb Size
19591034
1956-19581073
1951-19551129

Bulb Specifications

Description Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.1073
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.1129
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.1034

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