The Isuzu FRR 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 2004 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 FRR uses two distinct bulb types across its turn signal positions: the 1157 for the front and the 1156 for the rear, both of which are ANSI-standardized bulbs recognized in the United States and Canada.
All front turn signal entries for the Isuzu FRR Tilt Cab, spanning model years 1996-2004, specify the 1157 bulb.
All rear turn signal entries for the Isuzu FRR Tilt Cab, spanning model years 1996-2004, specify the 1156 bulb.
The 1157 is a dual-filament bulb, meaning it carries two separate filaments within a single envelope, allowing it to serve two lighting functions, such as turn signaling and parking illumination, simultaneously.
The 1156 is a single-filament bulb, meaning it is dedicated to one lighting function only, which aligns with its exclusive use in the rear turn signal position on the FRR.
Both the 1157 and 1156 operate on a 12-volt electrical system, consistent with standard automotive electrical architecture.
The 1157 carries a dual wattage rating of 21W and 5W, corresponding to its high-intensity and low-intensity filaments respectively, while the 1156 carries a single 21W rating.
The 1157 uses a BAY15d bayonet base, which features two offset pins to ensure correct orientation during installation, preventing the bulb from being seated in the wrong rotational position.
The 1156 uses a BA15s bayonet base, which has a single pin and allows installation in any rotational orientation, reflecting its single-filament design where polarity alignment is not required.
The BAY15d base of the 1157 and the BA15s base of the 1156 are physically distinct and not interchangeable, meaning the front and rear turn signal sockets on the FRR are incompatible with each other's bulb type.