Mitsubishi Fuso FK front and rear side marker bulbs use 89 size bulbs for replacement applications. The replacement chart covers vehicle production spanning 1986 to 1998.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mitsubishi Fuso FK uses the 89 bulb for both its front and rear side marker positions across the 1986-1998 model years.
The 89 is an ANSI-standardized bulb type recognized in both the United States and Canada, making it a widely available incandescent lamp within North American markets.
It is a single-filament bulb, meaning it serves one lighting function per socket rather than combining two functions such as running light and brake light into a single unit.
The 89 uses a BA15s bayonet base, which is a single-contact bayonet mount. The "s" designation in BA15s indicates a single contact pin, as opposed to the offset dual-contact BA15d base found on two-filament bulbs.
The bulb operates at 12 volts and draws 13 watts, placing it in the lower-wattage range of the BA15s bayonet family.
The 89 is described as a lower-wattage variant of the 1156. The 1156 shares the same BA15s bayonet base but operates at a higher wattage of approximately 26.9 watts, making the two bulbs physically compatible in terms of base type but electrically distinct.
Because the 89 and 1156 share the same BA15s base, substitution between the two is physically possible, though the difference in wattage means they are not electrically interchangeable without consideration of the circuit and socket ratings.
The consistent use of a single bulb type across all covered model years and across both the front and rear marker positions indicates a uniform socket specification throughout the FK's listed production span.