Test E: Locks Operate Intermittently

Check for loose connections in power door lock system. Tighten as necessary.
On Aerostar, inspect for poor relay ground. See WIRING DIAGRAMS . Repair as necessary.
On all models, inspect for poor ground at left power door lock switch. Repair as necessary.
Inspect for malfunctioning door lock switch. See POWER DOOR LOCK SWITCH under COMPONENT TESTS. Repair or replace as necessary.