hi, we bought our first audi last week a 98 a4. we have a strange problem with it that i was hoping someone may be able to answer. basically the blowers work fine but she you turn the heat on to demist the windscreen there is like a burning smell that goes after a bit and the screen mists up more rather than clears. could this be down to the pollen filter or something more serious? there is no smell when blowing cold.

any ideas?

thanks in advance.
Ian