Acura TL Dome Light Bulb Size

Additional Notes

• The Acura TL uses three distinct dome light bulb sizes across its 1995-2006 model years, with each size corresponding to a specific generation of the vehicle.
• The 12961 is a Philips-designated miniature wedge bulb in the T10 form factor, rated at 12V and 5W, and fitted with a W2.1x9.5d base. This wedge-style base differs fundamentally from the end-cap contact design used by festoon bulbs, making the types non-interchangeable.
• The Acura TL (2004-2006) uses the 12961 bulb for the dome light position.
• Festoon bulbs, such as the DE3425 and DE3175, are cylindrical lamps that make electrical contact through metal caps at each end rather than through a wedge or pin base. Both are rated at 12V and follow ANSI standards recognized in the United States and Canada.
• The DE3425 and DE3175 differ in physical length, at 41mm and 31mm respectively. Because festoon holders are sized to grip the bulb at a fixed span, these two sizes are not interchangeable with each other despite sharing the same base contact style.
• The 2000-2003 TL uses the DE3425 festoon bulb, which at 41mm is the longer of the two festoon types found in these specifications.
• The 1995-1999 TL uses the shorter DE3175 festoon bulb, with a 31mm length.
• The transition from the DE3175 to the DE3425 between the 1999 and 2000 model years reflects a change in the dome light housing design, as the longer bulb requires a wider-spaced festoon socket.
• The further transition from the DE3425 festoon type to the 12961 wedge type between the 2003 and 2004 model years indicates a change in socket architecture, since wedge and festoon holders are physically incompatible.
• When sourcing a replacement dome bulb for the Acura TL, the correct size is determined strictly by model year, as the three bulb types across this 1995-2006 range share no cross-compatibility.