Mack CM Courtesy Bulb Size
The Mack CM courtesy light requires 1003 and 912 bulb sizes for the interior lighting system. Data for the specific components covers the period from 1988 through 1991.
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 |
|---|---|
| 1991 | 1003 |
| 1990 | 912 |
| 1988-1989 | 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 |