The Mazda CX-9 dome light requires a DE3175 bulb size for proper installation and function within the interior lighting system. Available data for the specified component covers the range from 2007 through 2020.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The DE3175 is a festoon-type bulb measuring 31mm in length with end-cap contacts, operating at 12 volts, and conforming to ANSI standards for the US and Canadian markets.
The DE3425 shares the same festoon construction and 12-volt operating voltage as the DE3175 but has a longer body at 41mm, making the two bulbs physically incompatible with each other despite their similar design.
Festoon bulbs make electrical contact through metal caps at each end rather than through a base pin or wedge, which means correct length is critical for a secure fit in the lamp holder.
The Mazda CX-9 uses the DE3175 as the dome light bulb across the 2007-2017 model years, representing the most consistently specified bulb in these listings.
For the 2019-2020 Mazda CX-9, the DE3175 specification carries a "Without Adaptive Headlamps" qualifier, indicating that trim or equipment level affects dome light bulb fitment for those model years.
The rear dome light on the 2021-2022 CX-9 takes the longer DE3425 bulb, which differs from the DE3175 used in earlier model years and must not be substituted with the shorter unit.