The John Deere RSX850i uses a 3157NA bulb size for the front turn signal and a 3457 bulb size for the rear turn signal. The replacement chart covers 2013 through 2015 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 John Deere RSX850i uses two distinct bulb sizes across its turn signal positions: the 3157NA for the front and the 3457 for the rear, covering model years 2013-2015 for both positions.
Both the 3157NA and 3457 are dual-filament wedge bulbs built to the T25 form factor, operating at 12 volts with a 27W/7W power rating, where the higher wattage filament serves the turn signal function and the lower wattage filament serves a secondary function such as running or parking light duty.
Both bulbs conform to ANSI standards applicable in the United States and Canada, meaning they meet a defined set of electrical and photometric requirements rather than being proprietary specifications.
The primary distinction between the 3157NA and the 3457 is the glass envelope of the 3157NA, which is natural amber in color. This built-in amber tint produces a yellow-orange light output without requiring an amber lens on the fixture itself.
The 3457, used in the rear turn signal position, has a clear glass envelope. Its amber light output in a turn signal application is therefore dependent on the color of the vehicle's lens housing rather than the bulb itself.
Although the 3157NA and 3457 share the same T25 wedge base and identical voltage and wattage ratings, they are not interchangeable without consideration of the lens color. Installing a clear 3457 in a position designed for the natural amber 3157NA, or vice versa, would alter the color output of that light.