Fitted an after-market stereo in my a3 98.... worked fine then for some strange reason the other day it stoped working... when you turn the ignition on it comes on for a few seconds then goes straight off... if you turn the ignition on and off it does not come back on unless left a while... i have tried a different stereo and same problem please can somone help as i cant deal with not having music lol..... many thanks 
