electrical problem in my indicators or brakes 1997 corsa ls diesel 1.7?

hi I have a 1997(s reg) 1.7 diesel corsa ls. I have a electrical fault either in the indicators/hazards or brakes.
when I apply the brake the indicator relay makes a really annoying buzzing and the indicator light on the dash flickers dimley. the noise doesn't happen when the indicators are in use. the only time the indicator light on the dash works is when im braking.