GMC K15 Turn Signal Bulb Size
GMC K15 front and rear turn signal bulbs utilize 198, 1156, and 1073 sizes for front applications, with 198, 1156, and 1034 sizes for rear positions. The replacement chart covers 1966 through 1978 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
| Years | Bulb Size |
|---|---|
| 1973-1978 | 198 |
| 1968-1972 | 1156 |
| 1967 | 1073 |
| 1966 | 1156 |
Rear Turn Signal
| Years | Bulb Size |
|---|---|
| 1973-1978 | 198 |
| 1969-1972 | 1156 |
| 1968 | 1034 |
| 1967 | 1073 |
| 1966 | 1034 |
Bulb Specifications
| Description | Bulb Size |
|---|---|
| ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 2W. | 198 |
| 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. | 1034 |