The GMC Yukon brake light utilizes 7444NA, 7443, and 3057 bulb sizes depending on the specific production period for the vehicle. Data for the lighting components covers the range from 1992 through 2023.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 3057 bulb is the most frequently specified brake bulb across the GMC Yukon data, covering model years 1992-1999. It is a dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W high filament and 7W low filament, and meets ANSI standards for the US and Canada.
The 7443 and 7444NA bulbs share the same T20 wedge form factor and identical 12V, 21W/5W dual-filament ratings. Both meet ANSI standards for the US and Canada, which means the two types are electrically and physically similar.
Despite their shared electrical and physical characteristics, the 7444NA and 7443 are not the same bulb. The 7444NA features natural amber glass, which alters the color of the emitted light, while the 7443 uses clear glass.
The GMC Yukon (2023) is specified with the 7444NA, making the amber-tinted variant the designated brake bulb for that model year rather than the clear 7443.
The GMC Yukon (2014) uses the 7443, which lacks the amber glass coating of the 7444NA. Substituting a 7444NA in a 2014 application would change the light output color from clear to amber.
The T25 form factor of the 3057 is physically larger than the T20 form factor shared by the 7443 and 7444NA. These two groups are not interchangeable despite all three being wedge-base bulbs.
The 921 is a single-filament wedge bulb in the T15 form factor, rated at 12V and 16W. It serves only the Center High Mount Stop Light position on the Yukon for model years 1993-1997, a distinct application from the main brake bulb position.
The single-filament design of the 921 reflects its use in a dedicated stop-light-only position, whereas the dual-filament 3057, 7443, and 7444NA serve positions that combine both stop and tail light functions within a single bulb.
The T15, T20, and T25 designations indicate the width of the wedge base in units of one-eighth of an inch, meaning the 3057's T25 base is wider than the T20 bases of the 7443 and 7444NA, and both are wider than the T15 base of the 921.
All four bulb types specified across the Yukon brake lighting data conform to ANSI standards applicable in both the United States and Canada, indicating a shared regulatory framework governing their electrical and physical specifications.