Hazard lights not working

Had a quick look through the archives but couldn't see anything like my problem.  Should be a quick fix for those in the know I hope.

Sometimes when I flick the hazard switch the relay clicks and all the lights flash.

However, most of the time the lights don't come on at all and the relay makes a horrible buzzing noise.

In both instances the light mounted in the hazard switch comes on and it doesn't matter what else in the car is on/working/running.  The indicators work fine 100% of the time.  I replaced the relay and this hasn't helped.

Bad earth?  Faulty wires?  Faulty switch?  Any help on this would be much appreciated.

Try another relay , i would say its sticking ?

I know you have already but ……….

Cheers…………