Peterbilt 372 front and rear side marker bulbs utilize 194 and 1816 bulb sizes respectively. The replacement chart covers 1989 to 1995 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 372 uses two distinct bulb sizes across its side marker positions, with the type 194 assigned to the front and the type 1816 assigned to the rear for the 1989-1995 model years.
Both the 194 and 1816 are ANSI-standardized miniature wedge bulbs rated for 12-volt systems, making them compatible with the standard electrical architecture found in North American commercial vehicles.
The 194 bulb follows the T10 wedge form factor and draws 3.78 watts, placing it among the lower-wattage options in the miniature wedge category.
The 1816 bulb uses the T3.25 wedge form factor, which is physically smaller in tube size than the T10, and operates at 4 watts.
Although the 194 and 1816 share the same wedge-base design and 12-volt rating, their differing T10 and T3.25 tube sizes mean they are not interchangeable between the front and rear marker positions on the Peterbilt 372.
Both bulb types carry ANSI standardization applicable to the United States and Canada, indicating conformance to a shared North American specification rather than a regional or proprietary standard.
The wattage difference between the 194 at 3.78 watts and the 1816 at 4 watts is marginal, though the two bulbs remain mechanically distinct due to their respective form factors.