Plymouth Horizon Map Light Bulb Size

The Plymouth Horizon map light requires bulb sizes 168, 912, and 562 depending on the specific version of the component. Data for the bulb sizes covers the range from 1978 to 1985.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1985	168
1984	912
1978-1983	562

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168
ANSI standard (US & Canada). Wedge bulb (T15). Variant of 921. 12V, 12W.	912
ANSI standard (US & Canada). Festoon bulb, 44mm length, end-cap contacts. 12V, 12W.	562

Other Locations

Additional Notes

The Plymouth Horizon map light bulb specifications span the 1978-1985 model years, covering three distinct bulb types across that range.
The 562 bulb is the most frequently specified type in these records, appearing in the 1978-1983 model years, which accounts for six of the eight listed model years.
The 562 is a festoon-style bulb with a 44mm length and end-cap contacts, operating at 12V and 12W. Its festoon construction means it seats by pressing lengthwise between two spring clips rather than inserting into a socket.
The 1984 Plymouth Horizon uses a 912 bulb, a wedge-base type in the T15 form factor. It operates at 12V and 12W, matching the wattage of the 562 it replaced in the prior model years.
The 912 is noted as a variant of the 921 bulb. While both share the T15 wedge base, they are not identical, and substituting one for the other without confirming socket and wattage compatibility is inadvisable.
The 1985 Plymouth Horizon uses a 168 bulb, a miniature wedge type in the T10 form factor. At 12V and 4.9W, it draws significantly less power than the 912 or 562 bulbs used in earlier model years.
The shift from the 562 festoon base to the 912 wedge base between the 1983 and 1984 model years reflects a change in socket type, meaning the two bulbs are physically incompatible with each other's housings.
The further change from the 912 (T15) in 1984 to the 168 (T10) in 1985 represents another socket-type change, as T15 and T10 wedge bases differ in size and are not interchangeable.
All three bulb types in these specifications conform to ANSI standards applicable in both the United States and Canada.
The wattage difference between the 168 (4.9W) and the 912 or 562 (both 12W) is substantial, and the bulb types are not interchangeable regardless of any perceived similarity in function or voltage rating.