a) The connecting wire is broken or there is poor contact in the wire connection or in the contact switch. b) The fuse has blown. c) The battery is almost empty. d) Internal short circuit of the starter.
a) Solder or replace with a new connecting wire, degrease the contacts and tighten all nuts at the connecting points. b) Replace the fuse with the same power. c) Charge the battery. d) Avoid short circuit.