GMC Truck Brake Bulb Size
The GMC Truck brake light uses 1073 and 1129 bulb sizes for the rear lighting components. Data for the specific bulbs covers the period from 1950 through 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 | 1073 |
| 1950-1955 | 1129 |
Bulb Specifications
| Description | Bulb Size |
|---|---|
| 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 |