Chevrolet Silverado Tail Light Bulb Size

Additional Notes

• Three bulb families appear across the Chevrolet Silverado tail light specifications: the T20 wedge group (7443, 7444, 7444NA) and the T25 wedge group (3047, 3157). The T20 and T25 designations refer to the outer envelope width of the bulb, with T20 measuring 20/8 inch and T25 measuring 25/8 inch across the glass.
• The 7443 and 7444 are both dual-filament T20 wedge bulbs rated at 12V, 21W/5W under the ANSI standard for the US and Canada. The dual-filament design allows a single bulb to serve two functions, typically combining a brighter stop-light filament with a dimmer running-light filament.
• The 7444NA shares the same T20 form factor and 12V, 21W/5W electrical rating as the 7443 and 7444, but its glass envelope is tinted natural amber. This tint shifts the emitted light toward an amber color without requiring an amber lens on the fixture itself.
• The 3157 is a dual-filament T25 wedge bulb rated at 12V, 27W/7W. Its higher wattage values compared to the T20 group indicate greater light output on both the high and low filaments.
• The 3047 is a single-filament T25 wedge bulb rated at 12V, 27W. Unlike the 3157, it carries only one filament, meaning the socket it occupies is dedicated to a single lighting function rather than a combined stop and running light role.
• Although the 7443 and 7444 share identical voltage and wattage ratings, they are listed as distinct part numbers in the specifications. Substituting one for the other without confirming socket and base compatibility could result in an improper fit.
• The 7444NA is specified exclusively for the 2023 Silverado 1500, distinguishing it from the 7443 used on the 2023 Silverado 2500 HD. The amber glass of the 7444NA is therefore a trim-level or model-variant requirement rather than a universal choice across the 2023 lineup.
• For the 2020 Silverado 1500, the 7443 fitment is conditioned on the presence of halogen headlamps. This indicates that the tail light bulb specification on that model is linked to the headlamp technology installed on the vehicle.
• The 2014 Silverado is the only model year in the specifications where the 1500 and the 2500/3500 HD trims use bulbs from different size families entirely, with the 1500 taking a T20 (7444) and the HD variants taking a T25 (3047). In all other split-fitment years, both trims share the same bulb size.
• All bulb types listed across the specifications conform to the ANSI standard applicable to the US and Canadian markets, meaning physical and electrical tolerances are governed by that standardization body rather than manufacturer-specific dimensions.