The Oldsmobile Alero uses a 194 bulb size for front side marker applications and a 12961 bulb size for rear side marker positions. The replacement chart covers vehicle production spanning 1999 to 2004 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 Oldsmobile Alero uses two distinct bulb sizes across its front and rear side marker positions for the 1999-2004 model years.
The front side marker on the Oldsmobile Alero takes the 194 bulb across all six model years covered in the specifications.
The 194 is an ANSI-standardized miniature wedge bulb in the T10 form factor, rated at 12 volts and 3.78 watts.
Its ANSI standardization means the 194 bulb is produced by multiple manufacturers under a consistent specification, making it widely available across the US and Canadian markets.
The rear side marker position calls for the 12961 bulb across all six model years covered in the specifications.
The 12961 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12 volts and 5 watts.
Although both the 194 and 12961 share the T10 wedge form factor, their wattage ratings differ, with the rear 12961 drawing approximately 1.22 watts more than the front 194.
The W2.1x9.5d base designation on the 12961 describes a specific wedge base width and pin spacing, which is a standard reference used to confirm physical socket compatibility.
Because the 194 and 12961 carry different wattage ratings despite sharing a T10 form factor, substituting one for the other between front and rear positions falls outside the stated specifications.