For the 2017 Buick Regal, headlight bulb fitment depends on the factory headlight type. Models with halogen headlights use a 9012 bulb for both the low beam and high beam. Models with HID headlights use a D3S bulb for both functions.
The daytime running lights and parking lights also vary by headlight configuration: halogen-equipped models use 7443 bulbs, while HID-equipped models use integrated LED lighting. The front turn signal uses 7440A, and the rear turn signal uses 7440. Reverse lights use 921 bulbs.
The brake lights, center stop light, tail lights, and rear side markers are LED assemblies. Front side markers use 194NA bulbs. License plate lighting may use 194 or 7441 bulbs, depending on the specific lamp setup. Interior fitments include 6411 or 6428 for courtesy and interior lights, and 2825 or 98 for dome and map lights. Verify the headlight type and existing bulb or lamp assembly before ordering.