Mack TD700 Back Up Light Bulb Size

The Mack TD700 back up light requires a bulb size of 1156 for proper installation and function. Available information covers the specific time range from 2011 through 2017.

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
2011-2017	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Mack TD700 uses the 1156 bulb size for the back up light across the 2011-2017 model years.
The 1156 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 1156 bulb operates on a 12-volt electrical system and draws 21 watts, which is typical of incandescent automotive lighting applications.
The 1156 is a single-filament bulb, distinguishing it from dual-filament variants such as the 1157, which serves two lighting functions within a single housing.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a bayonet mount with a 15mm collar and a single contact pin at the base.
The single-contact BA15s base of the 1156 is not interchangeable with the BA15d base found on dual-filament bulbs, as the pin configuration differs between the two.