Toyota Corolla Tail Light Bulb Size

Additional Notes

• The three bulb types specified for the Toyota Corolla outer tail light position are the 7443, 3157, and 1157. All three are ANSI-standard dual-filament bulbs rated at 12 volts and are approved for use in the United States and Canada.
• The 7443 and 1157 share identical wattage ratings of 21W on the high filament and 5W on the low filament, while the 3157 draws more power at 27W and 7W respectively. Despite the shared wattage between the 7443 and 1157, the two bulbs are not interchangeable due to their different base types.
• The 7443 uses a T20 wedge base, and the 3157 uses a T25 wedge base. Both wedge-base bulbs are physically incompatible with each other and with the 1157, which uses a BAY15d bayonet base. The BAY15d base features two pins offset at different heights to prevent incorrect installation.
• The Toyota Corolla (2009-2016) outer tail light position requires the 7443 bulb, with a production date note for the 2011 model year specifying fitment from December 2010 onward.
• The 3157 bulb applies to the 1998-2008 model years, with the 2006 model year carrying a production cutoff of July 2006 and the 2004 model year specifying fitment from May 2004 onward. These date qualifiers indicate mid-cycle specification changes within those model years.
• The 1157 bulb with its bayonet base covers the widest span of model years in the specifications, applying to the 1968-1997 range with a gap in the data between 1992 and 1995.
• The T20 and T25 designations refer to the wedge base width in millimeters, making the 3157 physically larger at its base than the 7443. This size difference means the two wedge-type bulbs cannot be substituted for one another even though both fit into wedge-style sockets.
• The dual-filament design present in all three bulb types allows a single bulb to serve both the tail light and brake light functions within one housing, with the lower-wattage filament active for running lights and the higher-wattage filament activating under braking.