Mercury Mountaineer high and low beam headlight bulbs utilize 9008 and 9007 bulb sizes across the model line. The replacement chart covers vehicle production spanning 1997 to 2010 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 Mercury Mountaineer uses the same bulb for both high beam and low beam headlights across all listed years, as both functions are handled by a single dual-filament halogen bulb rather than separate single-filament units.
The 9007 and 9008 are both ANSI-standardized dual-filament halogen bulbs rated at 12V with a 65W high beam filament and a 55W low beam filament, making their electrical output identical.
The Mercury Mountaineer (1997-2006) takes the 9007 bulb, which uses a PX29t base, while the 2007-2010 model years require the 9008, which uses a P26t base.
The PX29t and P26t bases are physically different connector types, meaning a 9007 and a 9008 are not interchangeable despite sharing the same wattage and voltage ratings.
The bulb type changed from 9007 to 9008 between the 2006 and 2007 model years, representing a base configuration change rather than a change in power output.
Both the 9007 and 9008 are recognized under ANSI standards applicable in the United States and Canada, indicating compliance with North American automotive lighting regulations.