Q2 Determine If Cause Is Internal/External to Control Module

- Install 60-pin breakout box. Make sure the correct Econoline 4WABS overlay is installed.

- Measure resistance between breakout box pin 6 and known good chassis ground.

- Is resistance measurement less than 2000 ohms?

YES -- HCU reset switch or vehicle wiring is faulty. Go to Q3. Q3 Check Circuit 685 BK/W For Short to Ground

NO -- Faulty antilock brake control module. Replace. Go to Q7 to verify concern is resolved. Q7 Verify Concern Is Resolved