GMC C15 Tail Light Bulb Size
The GMC C15 tail light bulb uses 2 distinct sizes: 198 and 1034, with each bulb size corresponding to specific applications on the vehicle. The replacement chart covers 1967 to 1978 model years and documents the bulb specifications across the entire production range.
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 |
|---|---|
| 1969-1978 | 198 |
| 1967-1968 | 1034 |
Bulb Specifications
| Description | Bulb Size |
|---|---|
| ANSI standard (US & Canada). Miniature wedge bulb (T5). 12V, 2W. | 198 |
| ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W. | 1034 |