The Isuzu FVR front turn signal uses either 1157 or 1156 bulb size, while the rear turn signal requires 1156 bulb size. The replacement chart covers 1988 through 2011 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1156 and 1157 are the two bulb types specified across all front and rear turn signal positions on the Isuzu FVR, covering model years 1988 through 2011.
The 1157 is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base. Its dual-filament design allows it to serve both a primary signaling function and a lower-intensity secondary function within the same housing.
The 1156 is a single-filament bulb rated at 12V and 21W, mounted on a BA15s bayonet base. It is dedicated to a single lighting function, which is consistent with its use in rear turn signal positions throughout the FVR's production range.
The BAY15d base of the 1157 and the BA15s base of the 1156 are physically distinct. The BAY15d has two offset locking pins to accommodate its dual-filament design, while the BA15s has a single pin. These two bulbs are not interchangeable despite their similar appearance.
The Isuzu FVR front turn signal uses the 1157 from 1996 through 2011, with the Tilt Cab configuration noted specifically for 2002-2011 model years.
The front turn signal on the 1988-1994 Heavy Duty configuration uses the 1156, a single-filament bulb, rather than the dual-filament 1157 specified for later model years. The 1995 Heavy Duty front turn signal returns to the 1157.
The rear turn signal uses the 1156 across all recorded model years from 1988 through 2011, regardless of whether the configuration is listed as Heavy Duty or Tilt Cab.
Both the 1156 and 1157 conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and mechanical specifications across those markets.
The Tilt Cab designation appears in both front and rear turn signal entries for the 2002-2011 model years, indicating a specific cab configuration that applies to the FVR during that period.
Because the 1156 and 1157 share a visually similar bayonet-style base family but differ in pin configuration and filament count, substituting one for the other would result in an incompatible fit or incorrect circuit behavior.