Test 14, Check For VBAT Open To EDIS Module
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 1991 Ford Ranger, 1991 Ford RV Cutaway, 1991 Ford Pickup, 1991 Ford F-Super Duty, and 1991 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
With key off and ECA disconnected, set DVOM to 20-volt scale. Measure voltage between breakout box pins No. (+) J51 (VBAT E) and (-) J7 (BAT -). If voltage is greater than 10.5 volts, go to next test. If voltage is less than 10.5 volts, repair open circuit. Remove all test equipment, reconnect all components and check for fault codes.