The Pontiac G8 uses an H9 bulb size for high beam headlights and an H11 bulb size for low beam headlights. The replacement chart covers 2008 to 2009 model 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 Pontiac G8 uses two distinct halogen bulb types across its headlight system for the 2008-2009 model years: the H9 for high beam and the H11 for low beam.
Both the H9 and H11 are single-filament halogen bulbs operating on a 12-volt system, meaning each bulb handles only one lighting function rather than combining high and low beam duties within a single unit.
The H9 runs at 65 watts, while the H11 runs at 55 watts, reflecting the higher output demand typically associated with high beam applications.
The H9 uses a PGJ19-5 base and the H11 uses a PGJ19-2 base. Although both belong to the PGJ19 base family, the differing suffix numbers indicate physically incompatible mounting configurations, meaning the two bulb types are not interchangeable with each other.
Both bulb types conform to ECE standards, a regulatory framework governing lighting equipment across Europe and much of the world, and both carry approval for use in the United States as well.