The Subaru RX front and rear side marker bulbs both use a 194 size bulb for optimal illumination. The replacement chart covers 1985 through 1989 model 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 Subaru RX uses the 194 bulb for both front and rear side markers across the 1985-1989 model years.
The 194 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
It belongs to the T10 miniature wedge form factor, a design that uses a tapered plastic base to make direct contact with the socket rather than relying on metal pins or a bayonet fitting.
The 194 operates at 12 volts with a power draw of 3.78 watts, placing it in the low-wattage range typical of marker and courtesy lighting applications.
Because the same bulb size is specified for both the front and rear side marker positions, a single bulb type serves all four side marker sockets on the vehicle.
The T10 wedge base is widely used across many vehicle makes and models, which contributes to broad retail availability of the 194 bulb.
The wedge base design physically prevents incorrect installation orientation, as the tapered base seats in only one way within a compatible socket.
Any replacement or alternative bulb intended for these positions must conform to the T10 wedge base format and the 12V electrical specification to maintain socket compatibility.