The Isuzu NQR front turn signal requires a 1157 bulb size while the rear turn signal uses a 1156 bulb size. The replacement chart covers vehicle production spanning 1996 to 2013 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Isuzu NQR uses two distinct bulb types across its turn signal positions: the 1157 at the front and the 1156 at the rear, a fitment pattern that holds consistently across the 1996-2013 model years in the Tilt Cab configuration.
The 1157 is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, operating on a BAY15d bayonet base. The dual-filament design allows a single bulb to serve both a high-intensity signal function and a lower-intensity parking or running light function.
The 1156 is a single-filament bulb rated at 12V and 21W, mounted on a BA15s bayonet base. Because it carries only one filament, it is dedicated solely to the turn signal function at the rear position.
The BAY15d base of the 1157 and the BA15s base of the 1156 are not interchangeable. Although both use a 15mm bayonet base, the BAY15d has offset locking pins to accommodate the dual-filament orientation, while the BA15s has a single centered pin. Substituting one for the other is not physically compatible.
Both the 1157 and 1156 are ANSI-standardized bulbs recognized in the United States and Canada, meaning replacement units from multiple manufacturers are widely produced to the same specification.
All turn signal bulb specifications for the Isuzu NQR across the covered model years apply specifically to the Tilt Cab body configuration.