Hell I would try new bulbs, and then if that fails then try everything Josch stated. If the bulbs don't fix it take them back, you are out no money and easiest thing to check, if you don't have a test light.
Joe
1999 Contour SVT ~ Black w/Tan
Current Mods: Fog light rewire, 20% Tint, SVT Banner,Rockford Fosgate RFX-8340, 2-12" Bostwick SPL Subs & Audiobahn 600x2
Future Mods: Knauberizing it, lowering