The Peterbilt 349 uses a 194 bulb size for front side marker applications and an 1816 bulb size for rear side marker applications. The replacement chart covers 1986 to 1987 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 Peterbilt 349 uses two distinct bulb types across its side marker positions: the 194 at the front and the 1816 at the rear, covering the 1986-1987 model years.
Both the 194 and 1816 are ANSI-standardized bulbs recognized in the United States and Canada, meaning they conform to a defined set of electrical and physical specifications shared across manufacturers.
The 194 bulb is a T10 miniature wedge type, operating at 12V with a power draw of 3.78W, and it serves the front side marker position on the Peterbilt 349.
The 1816 bulb is a T3.25 miniature wedge type, operating at 12V with a power draw of 4W, and it serves the rear side marker position on the Peterbilt 349.
The T10 and T3.25 designations refer to the tubular envelope size of each bulb, with the numeric portion representing the width in eighths of an inch. The T3.25 envelope of the 1816 is notably narrower than the T10 envelope of the 194.
Both bulbs use a wedge base rather than a bayonet or screw base, meaning the base itself acts as the contact point and the bulb is held in place by friction within the socket.
Although the 194 and 1816 share the same 12V operating voltage, their wattage ratings differ. The 1816 draws slightly more power at 4W compared to the 3.78W of the 194, making the two bulbs non-interchangeable despite their shared voltage.
The physical difference between the T10 and T3.25 wedge bases further reinforces that the 194 and 1816 are not cross-compatible, as each is sized to fit a specific socket.