Steering problem
1999 Chevy Suburban 4 cyl Four Wheel Drive Automatic 169000 miles

my friend and I own the exact same year, model and make of veh. . . he called asking a couple of questions thinking we might have had the same problem, fortunately we haven't had this problem, but that also means that we don't know how to help our friend out. . . . . his power steering seems to lock up when the vehicle reaches a speed of 65MPH, we think that it might be the power steering sensor but are sure, we also don't know where this sensor would be located (is it in the pump or in the steering column?)