Good to keep this post running for updates as I was about to post "Lack of A/C-common causes please"
Got my '94 300Tdi Disco back in January and the A/C appears not to work, though I think some cooler
air comes through the vents compared to ambient ram air temp.
Have checked fuses and wondered if it was a simple regas required.
One point please guys, can you hear an audible click from the compressor clutch when turning the system
on and off ?