Freightliner Columbia Map Light Bulb Size

Additional Notes

• The Freightliner Columbia map light takes a 912 bulb across all listed model years from 2000-2017, representing an unbroken fitment consistency across the entire specification range.
• The 912 is a T15 wedge-base bulb, meaning it uses a tapering plastic base that presses directly into a socket without requiring a separate holder or bayonet twist to seat.
• At 12 volts and 12 watts, the 912 operates on a standard automotive electrical system and draws a relatively modest current load for an incandescent interior bulb.
• The 912 is classified as an ANSI standard bulb recognized in both the United States and Canada, indicating it conforms to a defined set of electrical and physical tolerances shared across manufacturers.
• The 912 is a variant of the 921 bulb. While both share the T15 wedge form factor and 12-volt rating, the 921 is rated at 18 watts, making the two types electrically non-equivalent despite their physical similarity.
• Because the 912 and 921 share the same T15 wedge base, the 921 will physically fit the Freightliner Columbia map light socket, but its higher wattage output differs from the factory specification.