I have a '92 F-150 351. After about 30 min of driving the ABS and red brake light comes on. The brake pedel actually feels better. No lose of braking and I havent tried to lock them up. If I shut the engine off and then restart it, the lights are out and they reappear after another 30 min. The sensor on top of the differential has been replaced. No effect. I now think that the control unit is bad. I am I even close?

 

Fix the condition that causes the red BRAKE light and you'll fix both.

Low brake fluid, faulty float or switch, parking brake switch, resistor/diode assy are all p[ossibilities.

Does the ABS light flash any code pattern ( a 1 or two digit value)?

Steve