Gotta be more specific. Do they all not work, or just the fronts, or just the rears? If just the front or just the rear, check the ground. IIRC, the rear ground is inside the trunk near the left side marker. Could be loose or corroded. The front has two grounds, IIRC, they may both be loose, or corroded. If neither end works, may be combination of bad grounds at both ends.

More investigation and detail, and we can help you out more.

Good luck,
Marq