For the 2001 Volkswagen Jetta, both the low-beam and high-beam headlights use a 9007 bulb. The supplied fitment data does not indicate a separate projector or non-projector headlight variation, so confirm the existing bulb before ordering.
Front fog lights may use either H3 or H3C. Front turn signals and parking lights use 3457A, while the front side marker uses 2821. The reverse lights use 7506, and the tail lights use 5007.
Rear lighting varies by body style: the sedan uses 7506R for the brake lights and 7506 for rear turn signals, while the wagon uses 7528 for both applications. The center stop light is listed as LED. Interior and utility applications include 6418 for the license plate and courtesy lights, 6411 or 6428 for the dome light, and 2825 or 98 for the glove box and map lights. Trunk lighting is body-style specific: sedans use 2825 or 98, while wagons use 6418.