The Lexus GS400 brake light utilizes a 7443 bulb size for illumination within the rear lighting assembly. Data for the specified component covers the period from 1998 through 2000.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Lexus GS400 uses two distinct bulb types across its brake lighting system for the 1998-2000 model years: the 7443 and the 168.
The 7443 is a dual-filament wedge bulb of the T20 form factor, rated at 12V with a 21W/5W output, meaning its two filaments serve separate functions at different wattages.
The higher-wattage filament of the 7443 activates under braking, while the lower-wattage filament typically serves a running light function, making it a common choice for positions that serve dual purposes.
The 7443 meets ANSI standards applicable in both the United States and Canada.
The inner brake and outer brake positions on the GS400 both use the 7443 for the full 1998-2000 production span.
The 168 is a single-filament miniature wedge bulb of the T10 form factor, rated at 12V and 4.9W, reflecting its lower-intensity application in the center high mount stop light.
The 168 also meets ANSI standards for the United States and Canada.
The T10 and T20 designations refer to the bulb's tubular width in units of one-eighth of an inch, meaning the two bulb types are physically incompatible with each other's sockets.
Because the 7443 is a dual-filament bulb, substituting a single-filament equivalent in the inner or outer brake positions would result in the loss of one lighting function.
The center high mount stop light on the GS400 uses the lower-wattage 168 rather than the 7443, consistent with the reduced output requirements of a supplemental stop light position.