Indicators have stopped working

This is probably a real easy fix, but I am a real newbie, so I do apologise. 
My indicators stopped working all of a sudden on my 1990 auto cab. The light comes on on the dash, but it doesn't flick on and off - it stays on constantly, and the indicators don't actually come on on the vehicle. I've changed the fuse, but that doesn't fix it. Any ideas? Cheers. 

is your hazzard lights working? maybe a problem with hazzard switch. the relay for this is no.21. Also look at fuse 4 and 19 and you can also check earth at the claw.