The International S1853FC uses a 168 bulb size for both front and rear side marker applications. The replacement chart covers 1987 to 1989 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 168 bulb is the sole bulb type specified for the International S1853FC across all listed model years and positions. It is an ANSI-standard miniature wedge bulb classified under the T10 form factor, rated at 12 volts and 4.9 watts.
The T10 wedge base design means the bulb is held in place by friction against the socket walls rather than by a bayonet or screw mechanism, which is a common trait of low-wattage marker and courtesy light applications.
At 4.9 watts, the 168 bulb draws a relatively low current, consistent with its role in side marker lighting rather than high-output functions such as headlamps or brake lights.
The International S1853FC uses the 168 bulb for both the front and rear side marker positions across the 1987-1989 model years, meaning a single bulb type serves all four side marker sockets on the vehicle.
The ANSI designation of the 168 bulb indicates it conforms to a standardized specification recognized in both the United States and Canada, establishing consistent electrical and physical parameters across manufacturers.
Because the front and rear side marker positions share the same bulb type on the S1853FC, there is no distinction in socket fitment between the two locations for the 1987-1989 model years.