The Isuzu Stylus brake light requires a 1157 bulb size for proper installation and function within the lighting assembly. Data for the specified component covers the range from 1991 to 1993.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Isuzu Stylus uses the 1157 bulb for its brake lights across the 1991-1993 model years.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output, fitted with a BAY15d bayonet base, and classified under the ANSI standard used in the US and Canada.
The dual-filament design of the 1157 allows it to serve two lighting functions from a single socket, with the higher 21W filament typically handling the brake function and the lower 5W filament handling a secondary function such as running lights.
The Center High Mount Stop Light on the 1991 Isuzu Stylus uses the P21W bulb, which differs from the 1073 used in the 1992-1993 model years.
The P21W is classified under the ECE standard, which is the regulatory framework used in Europe and most international markets outside North America.
The 1073 and P21W share the same BA15s bayonet base, meaning the socket type is physically compatible between the two bulbs.
Despite sharing a base type, the 1073 and P21W differ in wattage, with the 1073 rated at 13W and the P21W rated at 21W, which represents a meaningful difference in light output for a stop light application.
The 1073 is a single-filament ANSI-standard bulb rated at 12V and 13W, and it is considered a lower wattage variant of the more common 1156 bulb.
The shift from P21W to 1073 in the Center High Mount Stop Light between the 1991 and 1992 model years reflects a change from an ECE-rated bulb to an ANSI-rated bulb, which may have implications for direct substitution despite the shared base type.
The BAY15d base of the 1157 and the BA15s base of the 1073 and P21W are not interchangeable, as the BAY15d features offset pins to accommodate its dual-filament design, while the BA15s uses a single-pin configuration.