Volkswagen Polo my car alarm keps sounding

try to turn the sensor down +or- if this dose not work you have a wire shorting somewhere in the bulkhead if you cannot find it seek a auto elect he will proberbly find it in 2 mins

Remove the boot trim and check the boot lock for water penetration .Can come from outside or from rear washer .It has micro switch built into lock and can trigger alarm if water has been getting to it .