switch works-washer works-delay wiper works-it is the 1986 factory switch-wiper blades do not go down all the way-making a buzzing noise on the completed down side or off mode.for 1986 cougar/tbird. any info- or just a bad switch.
Try running a new ground the the wiper motor, the factory one is marginal at best. Worked on my old '86.:burnout:
http://www.coolcats.net/tech/troubleshooting/wipers.html
Would this be the same if your wipers were frozen in place and then suddenly let go. They now are not going to the home position. Work fine other wise.