Peterbilt 224 front side marker bulbs use 194 size while rear side marker bulbs use 1816 size. The replacement chart covers vehicle production from 1987 to 1994 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 Peterbilt 224 uses two distinct bulb types across its side marker positions: the 194 for front side markers and the 1816 for rear side markers, covering model years 1987-1994 in both cases.
Both the 194 and 1816 are ANSI-standardized miniature wedge bulbs rated for 12-volt systems, making them part of a widely recognized North American lighting standard applicable in both the United States and Canada.
The 194 bulb follows a 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 a T3.25 wedge form factor and is rated at 4 watts, a slightly higher wattage than the 194 despite both operating on the same 12-volt supply.
The T10 and T3.25 designations refer to the tubular envelope size of each bulb, with the numeric suffix indicating the width in eighths of an inch. The T10 is therefore wider than the T3.25, and the two are not physically interchangeable.
Because the 194 (T10) and 1816 (T3.25) have different wedge base profiles and envelope sizes, substituting one for the other in a given socket is not supported by the specifications for the Peterbilt 224.
The front and rear side marker positions on the Peterbilt 224 each use a single, consistent bulb type across the entire 1987-1994 production span, with no variation by year within either position.