Plymouth Cricket front and rear side marker bulbs both utilize a 1816 size bulb. The replacement chart covers vehicle production spanning 1971 to 1974.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth Cricket uses the 1816 bulb for both front and rear side markers across the 1971-1974 model years.
The 1816 is an ANSI-standardized bulb, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 1816 bulb follows the T3.25 form factor, which designates a tubular miniature wedge-base bulb with a width of approximately 3.25 eighths of an inch across the widest point of the envelope.
A wedge-base design means the bulb is held in its socket by the pinched glass base itself rather than by a separate metal cap, which is a common trait in low-wattage automotive marker lighting.
The 1816 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles of the Plymouth Cricket's era.
At 4 watts, the 1816 draws relatively low current, which is typical for side marker applications where continuous illumination is required without significant load on the vehicle's electrical system.
Because the same bulb number applies to all four side marker positions on the Plymouth Cricket (1971-1974), a single bulb type services the entire side marker system on the vehicle.
The T3.25 wedge format is not interchangeable with bayonet-base or screw-base miniature bulbs, even when voltage and wattage ratings are otherwise similar, due to the physical socket design.