Nissan GT-R Back Up Light Bulb Size

Additional Notes

• The 921 is the sole back up light bulb size specified for the Nissan GT-R across all listed model years from 2009-2024.
• The 921 bulb follows the ANSI standard recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical specifications shared across those markets.
• It uses a wedge-style base, designated T15, which refers to a tubular bulb body approximately 15 eighths of an inch wide that is held in its socket by friction rather than by pins or a bayonet mechanism.
• The 921 operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
• Its rated wattage of 16W places it in a moderate output range for a reverse light application, balancing visibility behind the vehicle with electrical load on the circuit.
• Because the wedge T15 base relies on a friction fit, substituting a bulb with a physically different base type would result in an incompatible fitment even if the voltage rating matched.
• Any replacement bulb intended for this application, including LED alternatives, would need to match the T15 wedge base configuration to seat correctly in the factory socket of the GT-R.