Check Selector Valve Connections
WARNING: This page is about a different car, the 1995 Ford RV Cutaway, 1995 Ford Econoline, 1995 Ford Cutaway, and 1995 Ford Club Wagon. However, it is still accessible from the selected car via links, so may be relevant.
Check push-connect connectors for tightness. If connectors are tight, go to next test. If connectors are not tight, repair or replace push-connect connectors as necessary and go to next test.