its got nothing to do with the button, the problem is if the handbrake is not staying up all the time this means your handbrake rachet is worn. on the rachet you have teeths so when you pull the hanbrake is grabs the teeth if they are worn it will go straight back down.
harry
September 2008
check the button is returning at top of handbrake .this is the normal problem that causes it not to work.it should spring out to activate rachet.