The Ram 4500 brake light requires 3057 or 1157 bulb sizes depending on the specific configuration of the vehicle. Data for the provided specifications covers the period from 2011 through 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ram 4500 brake light system draws from three ANSI-standard bulb types across its model years: the 3057, 1157, and 921, all rated for 12-volt systems and compliant with US and Canadian standards.
The 921 is a single-filament wedge bulb in the T15 form factor, rated at 16W, and serves as the center high mount stop light bulb for the Ram 4500 across the 2011-2018 model years.
The T15 wedge base of the 921 is a push-in connector type, meaning it does not use a bayonet or screw base, and is not interchangeable with bayonet-style sockets.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W high filament and a 5W low filament, and it serves as the brake bulb for the Ram 4500 in the 2011 and 2012 model years.
The BAY15d base of the 1157 features two offset pins, which prevents it from being inserted in the wrong orientation, and it is not physically compatible with single-pin or wedge-style sockets.
The 3057 is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W high filament and a 7W low filament, and it applies to the 2018 Ram 4500 brake light without projector headlamps.
Although both the 3057 and 1157 are dual-filament bulbs, their base types differ: the 3057 uses a wedge base while the 1157 uses a BAY15d bayonet base, making them non-interchangeable despite serving the same brake light function across different model years.
The 3057 carries a higher wattage output on its primary filament (27W) compared to the 1157 (21W), which reflects a difference in light intensity between the two brake bulb types used across the Ram 4500's production span.
The 2018 Ram 4500 brake bulb fitment is conditional, with the 3057 specified only for vehicles without projector headlamps, indicating that headlamp configuration affects brake bulb compatibility in that model year.
The 921 and 3057 share a wedge-style base but belong to different size classes, T15 and T25 respectively, and are not interchangeable with each other due to the difference in bulb body size.