What is the cause of Oil Light coming on when braking when oil pressure is O.K.

What is your question?

My Oil Light comes on when I brake or when in slow stop and go traffic. It goes off when I accelerate at speeds above 30mph. I have taken car to Ford Service several times, however, they cannot diagnose the problem because the light does not remain on. My oil pressure is good. They recently said they found some loose/dirty wiring which they tightened and clean but the problem remains.