I have an '87 3/4 ton chevy truck. The red Parking Brake Light comes on when the regular brake is applied fairly hard during driving. It will stay on for a while after this. I can sometimes turn it off by stopping again and pressing the brake again. Maybe it is just a fluke. Sometimes there is nothing I can do to shut it off. The light does still come on when I put the emergency brake on. The contact on the emergency brake pedal seems to be fine. What could possibly be causing this? Any help to get rid of this nuisance would be appreciated.