Mack R Courtesy Bulb Size
The Mack R courtesy bulb uses either 1003 or 912 size bulbs depending on vehicle configuration. The replacement chart covers 1981 through 1991 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.
Bulb Size by Year Range
| Years | Bulb Size |
|---|---|
| 1989-1991 | 1003 |
| 1988 | 912 |
| 1987 | 1003 |
| 1985-1986 | 912 |
| 1983-1984 | 1003 |
| 1982 | 912 |
| 1981 | 1003 |
Bulb Specifications
| Description | Bulb Size |
|---|---|
| ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W. | 1003 |
| ANSI standard (US & Canada). Wedge bulb (T15). Variant of 921. 12V, 12W. | 912 |