I have checked the fuses, relays, and even changed the wiper module. A shop charge $80 to diagnose, after a day’s work, wanted to charge additional $200 to continue since he wouldn’t find out what’s wrong. I am now driving by spraying Rain-x on the windshield everytime it rains.
Hopefully you have a test light probe to check where power is getting to. You may want to invest in a service manual so you can check things out yourself and save on service charges.
Edit:
After looking at some service data the trouble may be with the ignition switch. Check for power at fuse D in the panel under the hood. If you have voltage there then check fuse 18 in the dash panel with the ignition ON. If you have no power there then suspect the ignition switch as the problem.
I have Chilton manual but nothing on this problem.
Doesn’t it have the wiring diagram for the vehicle? I assume it does. When problems like this happen you try to find a common tie point for them in the circuit. Looking at the drawing, it looks like the ignition switch is the best suspect for this trouble.
I have an 03 Windstar and have had problems with the interior lights and power locks. I also have connections with a Ford dealer and the s/manager said the problem most likely is the ignition switch or wiring at the rear of the roof accessed by pulling the headliner. Windstars have always had problems!