Chevrolet Express Back Up Light Bulb Size

Additional Notes

• The 3157 is the most frequently specified back up light bulb across the Chevrolet Express lineup, appearing across the widest range of model years in these specifications.
• The 3157 is a dual-filament T25 wedge bulb rated at 12V with a 27W/7W output. In back up light applications, only one filament is typically active, with the second filament serving a separate circuit function in multi-purpose lamp housings.
• The 1156 and 1141 are both single-filament bulbs with a BA15s bayonet base, each rated at 12V and 21W. The BA15s base uses a single contact pin, which distinguishes it from dual-contact bayonet bases used in other automotive applications.
• Although the 1156 and 1141 share the same base type and wattage rating, they are not confirmed as interchangeable within these specifications, and substituting one for the other without verification of filament position and light output characteristics is not supported by the data provided.
• The Chevrolet Express 1500 uses a different back up light bulb than the 2500, 3500, and 4500 trims in several model years. Specifically, the 1500 takes a 2458 bulb while the heavier-duty trims take a 3157 in those same years.
• The 2458 bulb is specified exclusively for the Express 1500 in 2003-2005, 2009, 2011, 2013, and 2014. No technical description for the 2458 is included in the provided specifications.
• For the 2015-2022 model years, the Chevrolet Express uses a single bulb size, the 3157, across all trims without any noted sub-model distinctions.
• The Express transitioned from the 1141 to the 1156 between the 1999 and 2000 model years, and then from the 1156 to the 3157 between the 2002 and 2003 model years, based on the specifications provided.
• The 3157 is an ANSI-standardized bulb recognized in both the United States and Canada, which indicates broad retail availability across North American markets.
• Trim level is a determining factor for correct bulb fitment in multiple model years of the Express, meaning the gross vehicle weight rating or sub-model designation is a necessary reference point before selecting a replacement bulb for those years.