do they work with the hazard switch? if they do operate the hazard switch a good few times with a quick stab of the finger usually cures the fault. if they do not work with the hazards check the earth points at the lamps.
Yes they work with the hazard switch. I have tried stapping the switch a hundred times with still no joy.
I have also tried another stalk from the breakers. Ahhhh, not good fun!