I sometimes have problems with the plunger switch arrangement on the handbrake lever, and have to realign it from time to time, as the plunger on the switch keeps misaligning with the metal bit that presses it when you let the handbrake off. Took me a while to find that one.. I find if I let the handbrake right off, the warning light stays on, but goes out if I just lift the lever a smidge.