Mack MR Courtesy Bulb Size
The Mack MR courtesy bulb uses 2 distinct sizes: 912 and 1003, with each bulb size corresponding to specific vehicle configurations. A replacement chart documents the bulb specifications across the 1981 to 1997 production range for this truck model.
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 |
|---|---|
| 1997 | 912 |
| 1993-1996 | 1003 |
| 1992 | 912 |
| 1990-1991 | 1003 |
| 1988-1989 | 912 |
| 1984-1987 | 1003 |
| 1983 | 912 |
| 1982 | 1003 |
| 1981 | 912 |
Bulb Specifications
| Description | Bulb Size |
|---|---|
| ANSI standard (US & Canada). Wedge bulb (T15). Variant of 921. 12V, 12W. | 912 |
| ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W. | 1003 |