why my hazard warning light flash continuosly vauxhall vivaro 02?

i have a problem where my hazards started to flash all the time thus causing my battery to go flat i bought a new hazard warning light switch but problem still there but today looked at it again and found if you operate side lights or headlights the problem goes away and acts normal indicators work correctly hazards work correctly but the minuite you turn lights off the hazards start to flash again and the only way to stop them is to remove the 10 amp fuse which then cuts power to backlight on dash all indicators and immobilizes van please could sum 1 suggest a remedy