I have a Vauxhall zafira A 2005. Recently we had quite a bit of snow here in the uk. Since then my wipers are not working correctly. Drivers side is fine but passengers side won’t move. I checked the bolt to find it loose so tightened it and started working but the wipers are hitting each other every time. I tried adjusting the position but it still happens. I never had this problem before the snow so any ideas what to check next?