The following is a ford-starter solenoid wiring diagram illustrating the importance of a wiring setup. The following is a wiring diagram for an old machine where the relay, also known as a solenoid, gets 12V in on the Ignition Switch, and the relay then bridges the Battery Cable to the Starter Cable terminals, which spins the starter. At the same time, you can move the starter cable to the batter side and run a smaller wire from the output of the relay/solenoid to the small terminal on the starter. In addition to this, you could run the starter cable directly to the battery, in which case the positive battery cable to the relay could be made smaller since it will not be carrying the starter's load.
