The Jeep J10 front and rear turn signal bulbs utilize either 1157 or 198 size bulbs depending on production specifications. The replacement chart covers 1974 to 1988 model years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Jeep J10 uses two distinct bulb types across its turn signal specifications: the 1157 and the 198, both of which are ANSI-standard bulbs recognized in the US and Canada.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output, mounted on a BAY15d bayonet base. The dual-filament design allows it to serve two brightness levels within a single housing, which is typical for combined turn signal and parking light functions.
The 198 is a miniature wedge bulb in the T5 form factor, rated at 12V and 2W. Its low wattage places it in the category of low-intensity indicator lighting.
The Jeep J10 front turn signal uses the 1157 bulb for model years 1979-1988 and the 198 bulb for model years 1974-1978.
The rear turn signal follows the same pattern, with the 1157 specified for 1979-1988 and the 198 specified for 1974-1978.
The front and rear turn signal bulb sizes are identical for every model year covered in the specifications, meaning both positions share the same bulb type in any given year.
The 1157 and 198 are not interchangeable. They differ in base type, filament count, wattage, and physical form factor, making substitution between the two incompatible without modification.
The BAY15d bayonet base of the 1157 features offset pins, a design that prevents incorrect insertion orientation and distinguishes it from single-filament bayonet bulbs with symmetrical pins.
The transition from the 198 to the 1157 between the 1978 and 1979 model years represents a significant change in both wattage and bulb construction across the J10 turn signal system.
The 1157 operates at a substantially higher wattage on its primary filament (21W) compared to the 198 (2W), reflecting a fundamental difference in the intended output intensity between the two bulb types used across the J10's production span.