Fiat 500X Map Light Bulb Size

Additional Notes

• The 12961 is a Philips part number designating a miniature wedge-style bulb in the T10 form factor, operating at 12 volts and rated at 5 watts.
• The T10 designation refers to the bulb's tubular shape, with the number indicating a width of 10 thirty-seconds of an inch, a standard sizing convention used across the miniature bulb industry.
• The base type on the 12961 is W2.1x9.5d, a wedge base in which the glass envelope itself acts as the retention mechanism rather than a separate metal base, making it a tool-free press-fit installation.
• The Fiat 500X uses the 12961 bulb for its map light across the 2016-2021 model years, representing the full documented production span in these specifications.
• Because the W2.1x9.5d wedge base is a widely adopted standard, the 12961 is cross-compatible with other bulbs sharing the same base type and voltage rating, provided the wattage and physical size of the replacement also match the original.
• At 5 watts on a 12-volt circuit, the 12961 draws approximately 417 milliamps, which is consistent with low-current interior lighting applications such as map and courtesy lights.
• Substituting a bulb with a higher wattage rating than 5W in this application risks exceeding the thermal tolerance of the surrounding trim and the current rating of the socket, as the circuit is designed around the original specification.