The Lexus RX300 back up light requires a bulb size of 7440 for proper installation and function within the rear lighting assembly. Data for the specific bulb requirements covers the period from 1999 through 2003.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus RX300 uses the 7440 bulb across all back up light positions for model years 1999-2003.
The 7440 is an ANSI-standardized bulb type recognized across the United States and Canada, meaning it conforms to a defined set of electrical and physical specifications shared by all compliant manufacturers.
The 7440 is a single-filament bulb, which means it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light duties simultaneously.
The bulb operates at 12 volts and draws 21 watts, placing it in the mid-range of standard automotive wedge bulb wattages.
The 7440 follows the T20 wedge form factor, a designation that refers to the physical shape and base style of the bulb rather than its electrical output.
The RX300 carries two distinct back up light positions in its specifications: a general back up light and an inner back up light, both of which share the same 7440 bulb size across the listed model years.
For the 2000 Lexus RX300 inner back up light, the 7440 specification is noted with a production cutoff of July 2000, indicating a mid-year assembly change that affects fitment for vehicles produced after that date.