Ford Explorer Map Light Bulb Size

Additional Notes

• The Ford Explorer map light draws from three distinct bulb types across its model history: the 168, 578, and 906, all of which conform to ANSI standards recognized in the United States and Canada.
• The 168 bulb is a T10 miniature wedge type rated at 12V and 4.9W. Its wedge base design means it is held in place by the socket itself rather than by a separate locking mechanism.
• The 906 bulb shares the same T10 miniature wedge form factor as the 168 but operates at a higher wattage of 8W at 12V, making the two bulbs physically similar yet electrically distinct.
• Because the 168 and 906 share the T10 wedge base, they may fit the same socket physically, but substituting one for the other introduces a wattage mismatch that can affect circuit load and light output.
• The 578 is a festoon-type bulb with a 41mm length and end-cap contacts. Unlike wedge bulbs, festoon bulbs seat between two spring clips rather than inserting into a wedge socket, making it incompatible with sockets designed for the 168 or 906.
• The 578 festoon bulb is rated at 12V and 12W, a notably higher wattage than either the 168 or 906, reflecting its different construction and contact type.
• The Ford Explorer (2011-2019) uses the 168 bulb for the map light across all nine of those model years, representing the longest uninterrupted run of a single bulb type in these specifications.
• The 578 festoon bulb is specified for the Ford Explorer map light across the 2002-2010 model years, a span of nine consecutive years.
• The 1993-1994 model years specify the 906 bulb, placing them as the only years in the entire listed range to use that particular type.
• The Ford Explorer map light specification shifts between bulb types at several points in its history, meaning socket type and wattage must be confirmed against the specific model year before a replacement bulb is selected.