Diamond Reo C116 high beam headlight bulbs use H5001 size while low beam headlight bulbs use H5006 size. The replacement chart covers vehicle production years spanning 1990 to 1993.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Diamond Reo C116 uses the H5001 bulb size for high beam headlights across the 1990-1993 model years.
The H5001 is a 4-inch square sealed beam unit operating at 12V. Because it is a sealed beam design, the entire unit is replaced rather than an internal filament or capsule.
The H5001 conforms to ANSI standards recognized in both the United States and Canada.
Low beam headlights on the C116 use the H5006 bulb size across the same 1990-1993 model years.
The H5006 is a 5.75-inch round sealed beam unit, also rated at 12V and also requiring full unit replacement rather than bulb-only replacement.
The H5006 likewise conforms to ANSI standards applicable in the United States and Canada.
Because the H5001 and H5006 are physically distinct sealed beam formats, one is not interchangeable with the other. The square 4-inch H5001 serves the high beam position, while the round 5.75-inch H5006 serves the low beam position.