The wipers on my '88 Mark VII do not work in any position except when I pull out to spray washer solvent and then they go back and forth as they should. If when doing this I put the wiper control in an on position they go back and forth to clean as they should but then do not drop down all they way until I put the wiper control back to the off posiition. Any idea's?? Also, the wiper control arm(no idea what it should be called) is brand new. My brother and I actually tracked down a new one in a Ford dealer.