Gear box reversing switch

Hi,

     taken the golf out of the garage first time since last summer and do not have any reversing lights.
     I have tested the terminals on the switch (the one on the gearbox) with a continuity meter and getting an open circuit when the gear selector is in reverse or otherwise. Also removed the switch and again tested pushing the plunger in manually and giving just an open circuit reading. Am I correct in thinking the switch should give an closed reading when reveerse is selected or the plunger is pushed in?

      Is there anything else I can check or adjust before taking the plunge and getting a new switch.

     Thanks.  

to test the wiring just loop the pins on the plug with wire and put it into reverse ignition on, if lights come on wiring is all fine, try a new switch

the switch should be open circuit normally, then closed when you press in the plunger