The air con on my fabia 1.4 (2001) only seems to come on intermittently. When it does work it's great, nice and cold. When it doesn't work it blows hot air. Sometimes it'll suddenly kick in when the button hasd been on for a while with no apprent reason. Any ideas what's going on/how I can fix it? Thanks!

Fault code check is required, possible fault with the evaporator temp sensor i'd say.