Pontiac Aztek front side marker bulbs use 194 size while rear side marker bulbs use 3157 size. The replacement chart covers 2001 to 2005 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 Pontiac Aztek uses the 194 bulb for the front side marker position across all 2001-2005 model years.
The 194 is a T10 miniature wedge bulb rated at 12V and 3.78W, conforming to the ANSI standard recognized in both the US and Canada.
The low wattage of the 194 reflects its role as a small marker lamp rather than a primary lighting source.
The rear side marker position on the Pontiac Aztek uses the 3157 bulb across all 2001-2005 model years.
The 3157 is a T25 dual-filament wedge bulb rated at 12V with a 27W/7W output, also conforming to the ANSI standard recognized in both the US and Canada.
The dual-filament design of the 3157 means the bulb contains two separate filaments operating at different wattages, which allows it to serve more than one lighting function within a single housing.
The front and rear side marker positions on the Aztek require different bulb sizes, and the two types are not interchangeable with each other.
The T10 and T25 designations refer to the bulb's tubular envelope size, with T25 being physically larger than T10, which further distinguishes the two positions mechanically.