Kenworth T660 high beam headlight bulbs use 9005 size while low beam headlight bulbs use H11 size. The replacement chart covers 2008 to 2011 vehicle 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 Kenworth T660 uses two distinct bulb types across its headlight system for the 2008-2011 model years: the 9005 for high beam and the H11 for low beam.
The 9005 is an ANSI-standard single-filament halogen bulb rated at 12V and 65W, fitted with a P20d base, and is the designated high beam bulb across all four model years in the specifications.
The H11 is an ECE-standard single-filament halogen bulb rated at 12V and 55W, fitted with a PGJ19-2 base, and serves as the low beam bulb across the same 2008-2011 span.
The 9005 and H11 carry different base types, P20d and PGJ19-2 respectively, meaning the two bulbs are not interchangeable with each other despite both being single-filament halogen units operating at 12V.
The 10-watt difference between the 9005 (65W) and the H11 (55W) reflects a deliberate engineering distinction, as high beam applications typically require greater light output than low beam configurations.
The H11 operates under the ECE regulatory standard, which governs lighting equipment across Europe and many other markets worldwide, though it also carries approval for use in the United States.
The 9005 operates under the ANSI standard, which applies specifically to the United States and Canada, making it a North America-oriented specification in contrast to the internationally scoped H11.