Pontiac Trans Sport high beam and low beam headlight bulbs utilize 9004, 9005, and 9006 sizes depending on beam type and model configuration. The replacement chart covers 1990 to 1998 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 9004 bulb is a dual-filament halogen type operating at 12V with a P29t base and a 65W/45W rating, where the higher wattage serves the high beam filament and the lower wattage serves the low beam filament. This dual-filament design means a single 9004 bulb handles both beam functions within one housing.
For the Pontiac Trans Sport, the 9004 bulb serves as both the high beam and low beam headlight in the 1997-1998 model years, consolidating both functions into one bulb per side rather than using separate bulbs for each beam.
The 9005 bulb is a single-filament halogen type rated at 12V and 65W with a P20d base. Because it carries only one filament, it is dedicated exclusively to high beam output.
The 9006 bulb is also a single-filament halogen type but is rated at 12V and 55W with a P22d base, making it a lower-wattage counterpart to the 9005. It is dedicated exclusively to low beam output.
In the 1990-1996 model years, the Trans Sport uses separate bulbs for each beam function, with the 9005 handling high beam duties and the 9006 handling low beam duties. These two bulbs are not interchangeable with each other due to differing base types, wattage ratings, and filament configurations.
The P20d base of the 9005 and the P22d base of the 9006 are physically distinct from the P29t base of the 9004, meaning none of these three bulb types are cross-compatible with one another at the socket level.
All three bulb types listed in these specifications conform to ANSI standards applicable in both the United States and Canada, indicating standardized electrical and photometric performance requirements across that market.
The wattage difference between the 9005 at 65W and the 9006 at 55W reflects their respective roles, as high beam applications generally draw more power to produce a longer, wider light pattern than low beam applications.