For the 2019 Audi Q7, headlight bulb fitment depends on the factory headlight type. Models with HID headlights use a D5S bulb for both the low beam and high beam. Models with LED headlights use LED lighting for both functions. The fitment data also lists LED for the high beam and low beam without a headlight-type condition, so confirm the installed headlamp system before ordering replacement parts.
Beyond the headlights, the front fog lights and reverse lights use 921 bulbs. Front turn signals are listed as 64132 with HID headlights and LED with LED headlights. Most other exterior lighting is LED, including the brake lights, center stop light, cornering lights, daytime running lights, license plate lights, front side markers, tail lights, rear turn signals, step lights, and vanity lights. The rear side marker uses a 2821 bulb. Interior fitment includes LED map, dome, glove-box, trunk, and vanity lights, with 2825 and 98 also listed for interior lighting.