the truck is 1999 ford super duty, 550 and it has over 100,000 miles on it but used now for only small trips to store and has not towed anything for two years. hoping this is not expensive to fix.
Probably just a sensor. Most likely one that senses wheel speed. I don't know the cost, but I wouldn't think it would be too expensive. Have it checked out by your ford dealer to make sure.
Check your Ground cables, and make sure that you have a thick one to the engine, and a thin one to the body. Sometimes the computer gets a low voltage signal from having a bad ground. This causes the computer to send a fault code, resembling a problem.
simple first check brake fluid in reservoir top up with D.O.T.3 brake fluid only. this is probably a 4 wheel system that uses a sensor at both front wheels and a single sensor at top of rear differential if you are electrically savvy you can measure the sensor resistance at the quick disconnect near each sensor. i recommend testing the front sensors first as they get flexed from steering and are most suspect. typically resistance values range from 500 ohms to 1300 ohms , now watch the meter carefully and flex the sensor cable if the meter reads infinite resistance [open circuit] you have found the offending sensor, any other anti lock repair should be refer-ed to a competent shop as it can get very involved please be careful while jacking and blocking as you can only be dead once. good luck
