the starter relay what is it use for
the starter relay just like any relay uses a small current activated by a switch (key in ignition) to allow a larger current to flow to a component (starter). This allows the starter to use it's 1000's of amps without that large current flowing through your key switch in the dash. Typical relays use the lower current to magnetize a coil that pulls a connector for the larger current to flow through. Signal from switch to ground, then battery voltage to starter.