Chevrolet Colorado Parking Light Bulb Size

Additional Notes

• The parking light bulb specifications for the Chevrolet Colorado span model years 2004 through 2020, with three distinct bulb sizes used across that range: the 3757NA, the 7443NA, and the 7444NA.
• All three bulb types carry the "NA" suffix, which denotes natural amber glass. This coloring is built into the glass envelope itself rather than applied as a coating, producing an amber output without the need for an amber-tinted lens.
• The 3757NA and 7443NA are both dual-filament wedge bulbs operating at 12V with a wattage split of 21W and 5W, corresponding to a higher-intensity filament and a lower-intensity filament within the same housing.
• The 3757NA is a T25 wedge bulb, while the 7443NA and 7444NA are T20 wedge bulbs. The T25 and T20 designations refer to different body sizes, meaning the 3757NA is physically larger than the 7443NA and 7444NA and is not interchangeable with them.
• The Chevrolet Colorado (2004-2012) uses the 3757NA, making it the most frequently specified bulb across the listed years, appearing in nine of the fifteen model years covered.
• The 7443NA is specified for model years 2015-2017, and the 7444NA is specified for model years 2018-2020. Both share the T20 form factor and the same 12V, 21W/5W electrical ratings.
• Although the 7443NA and 7444NA share identical voltage and wattage ratings and the same T20 wedge base, they carry different ANSI part numbers, which indicates a distinction in their specifications that warrants attention when selecting a replacement.
• The dual-filament design of all three bulb types allows a single bulb to serve two lighting functions, with the 21W filament typically associated with a brighter signaling function and the 5W filament associated with a lower-intensity running or parking function.