The Jeep Grand Wagoneer front turn signal requires a 1157 bulb size, while rear turn signal applications use either 1156 or 1157 bulb sizes. The replacement chart covers 1984 through 1993 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 1157 bulb is a dual-filament type operating at 12V with a 21W main filament and a 5W secondary filament, fitted with a BAY15d bayonet base. The BAY15d base features offset pins, which physically prevents it from being inserted into sockets designed for single-filament bayonet bases.
The 1156 bulb is a single-filament type operating at 12V at 21W, fitted with a BA15s bayonet base. The BA15s base features symmetrically placed pins, making it incompatible with the offset-pin BAY15d socket used by the 1157.
Both the 1157 and 1156 are ANSI-standardized bulbs recognized across the US and Canada, meaning replacements conforming to those ANSI designations will meet the same electrical and physical specifications regardless of manufacturer.
The Jeep Grand Wagoneer front turn signal position uses the 1157 bulb consistently across the 1984-1991 model years covered in the specifications.
The rear turn signal position on the Grand Wagoneer transitioned from the dual-filament 1157 to the single-filament 1156 between the 1985 and 1986 model years.
From 1986-1991 and again in 1993, the Grand Wagoneer rear turn signal uses the 1156 bulb, while the front retains the 1157 throughout its listed range. This means the front and rear positions require different bulb types and are not interchangeable for those years.
For the 1984-1985 Grand Wagoneer, both the front and rear turn signal positions share the 1157 bulb, making those two positions interchangeable with each other during that period.
The difference in filament count between the 1157 and 1156 reflects a functional distinction. A dual-filament bulb such as the 1157 can serve both a running light and a turn signal function from a single housing, while the single-filament 1156 serves only one function at a time.