park lights don't work

I have a 96 Windstar and the park lights do not work.....the brake, headlights and turn signal lights do work though. I have tried the fuses, bulbs and the switch.......any suggestions???

thanks

Have you checked with a test lamp to see if there is voltage/battery at the lamp socket? If there is voltage then it may be a missing ground. If no voltage then you'll have to back up into the harness until you find where the problem lies. A test lamp on the parking light terminal on the switch would be a good check also. Good luck.