Air Brake Antilock problems of the 1997 Jeep Wrangler

Vehicle has anti-lock brakers on all 4-wheels. On slick roads,grass,mud, snow, front wheels lock up and you dont have any control as you cant steer. The lock is working on front brakes but not the anti. This is very dangerous and I dont drive in snoe. I have reported numerous time to dealer and Chrysler. They say there is nothing wrong but service mgr almost went in ditch. Last time I called Chrysler the lady hung up on me.