dash gauges/warning lights not working

[83rona]

Hey guys I've recently brought a tt140 corona and the fuel/temp gauges don't work, also the handbrake light and oil pressure light don't light up. I managed to get them going the other day by changing fuses but when I hit the demister switch they all stopped working again.

I've checked and changed the fuse and it seems all good there but they still don't work. Any ideas what could be the problem? Thanks

The car has a 2t engine if that helps at all.