Renault Megane 1998 Auto

Hi,
Wonder if someone can help? I have a Megane 1998 RT AUTO. Sometimes when driving I hear a slushing noise coming from the passengers side by the glove compartment. I have had it checked out but noone can see where it is coming from. There is no water in the body work collecting anywhere. The front screen mists up but noone seems to be able to help. Anyone have any ideas??

Any Mr Slushy machines in your car? could the problem be behind the dash? maybe a break in the seal at the bottom of your window or if you look under the bonnet at the back there are them vents thingys (technical term) which open, have a look in there or maybe underneath the car in the problem area, after all if it aint inside its outside right? sorry I cant be of much real help.