TD4 Reverse light switch

does anyone know what breaks on the switch as mine looks perfect next to the mew one there cant be much inside it thanks sin advance

i do not think you can easily take them apart but all it usually is on a reverse light switch is a plunger that makes contact , well at least that's what they used to be, and when you move your gear stick it touches the plunger and presses it in , which in turn makes the contact . hope this helps