that's one thing I thought too initially-indicator relay- But then I thought about it and decided if it was, it would affect all of the indicators on the car as typically you only have one indicator relay. besides, if its only affecting one particular indicator-bearing in mind the car has 6 indicator bulbs-the problem would obviously have to be with the problematic bulb in the first instance. When you activate your indicator stalk to left or right, you send a signal to the indicator relay to operate. The signal produced by the relay then energises a circuit which is ,at some point ,split into 2 circuits (left and right, for the two sides of the car),usually at the stalk, and depending on which position your indicator stalk is in, you are either directing that signal from the relay to one sides circuit or the other, thus if one particular bulb doesnt work-say its missing, or blown, the others on that circuit flash faster due to lower resistance on the circuit (and please correct that any sparky's out there as I am not an auto electrician lol). in the case of the Hazard lights, that relay is wired into both circuits and isnt split as such, hence all bulbs flash at the same time irrespective of where the stalk is positioned. Good luck!!