Dash Brake Lamp Indicator
 

I have a 87 Accord and the brake lamp fault light on the dash is on. All my bulbs are good & light up and the plastic target attached to the brake pedal that pushes the sensor when the brake is off is ok (when this is missing the dash lamp lights and as I remember the tail lights light up). Any ideas on what my problem is? If the car is off and started without hitting the brake pedal the indicator light is off, but as soon as I hit the brake pedal it comes on and won't go out. Thanks.