As the connection is internal I doubt it will be dirty. Most probably one of your belts has snapped or your microswitch has fallen out of the casing. The belt pushes on the micro-switch so if the belt breaks the circuit is "open" causing your light to come on. Again, if the switch has fallen out, the m/s will be open. Look under the car for a wire dangling down.

If it's fallen out, silicon around the edge once it's back in position. If your belt has snapped then either replace it or remove the system/ bulb should you feel the need. Bear in mind if you remove the bulb your abs will not function correctly and with the light on it will not pass an MOT.