I've just been to look at a 2006 Vectra 1.9 CDTI Estate to replace our 2006 1.8 Hatchback due to space issues with two babies. However when I took it out I noticed that the light on the "AUTO" button of the climate control doesn't illuminate. Could this be a tell tale fault light i.e if it's not lit it doesn't work or just simply a bulb that blown. I tried the button and it seemed to work ok but didn't really give it chance for the aircon to kick in. Any advice will greatly be appreciated.