1998 passat turbo key recoding

[passat turbo]

hi ive had my car a cpl of months now and never had the remote key fob working its the non flip one with 2 buttoms ive bought 2 new batteries today 2016 ones and fitted them the light is staying on very dimly then when you press both buttons together it goes off and illimunitates when you press either button but does nothing on the car any one any ideas what i need to do to sort it