Test 8, Check Dis Module Ignition Ground
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, check resistance between breakout box pins No. J2 (IGND D) and J60 (BAT -). If resistance is more than 5 ohms, go to next test. If resistance is less than 5 ohms, go to TEST 10.