Mack U Back Up Light Bulb Size
The Mack U back up light utilizes 1156 and P21W bulb sizes for illumination purposes. Available information covers the specific time period from 1981 through 1989 for the vehicle.
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 | US Type | EU Type | Shop |
|---|---|---|---|
| 1981-1989 | 1156 | P21W | Check Price |
Bulb Specifications
| Description | Type | Shop |
|---|---|---|
| ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W. | 1156 | Check Price |
| ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W. | P21W | Check Price |