For the 2002 Buick Regal, the supplied fitment data lists a 9005 high-beam bulb. No low-beam bulb is listed, so verify the original low-beam bulb before ordering a replacement. The fog lights use 893 bulbs.
Useful exterior replacements include 4157NA bulbs for the front turn signals and parking lights, 1156 for the reverse lights, 3057R for the brake lights, and 3057 for the rear turn signals. The center stop light uses 921, while the front and rear cornering lights use 3156. Side markers use 194NA bulbs.
Several locations have more than one listed option. License plate and glove-box applications may use 194 or 7441 bulbs, and tail-light fitment includes 194, 7441, and 3057R. For the courtesy light, compare the original bulb: 168 or 917 is listed for Option 1, while 2721 is listed for Option 2. The dome light uses 906, map lights use 168 or 917, and the instrument panel uses PC74.