(Devinci40, I stumbled across some pics.) The idea is to inspect this contact or copper bridge (red rectangle). By design, the
headlight wires runs through the start button so that when you press in the start button to start the engine, it breaks the circuit for the headlight momentarily shutting off the headlight so there's more electricity directed to the starter motor and also less electrical draw on a (weak) battery, so on. A disadvantage is that the headlight electricity heats up the copper bridge on some bikes. This causes the copper bridge to eventually sink into its nylon substrate. It's repairable by plucking up the copper bridge if it's not as bad as below.

Release the 4 barbs from their 4 slots to separate the parts.

