forgot to mention that a lot of the old ford systems used a starter that had no solenoid on it to draw the starter drive into the flywheel. the starter was energized through a simple cable connection directly on the starter motor, this put power directly into the windings of the starter and made a magnetic field. this filed drew/moved a lever on the side of the motor, in the tin shroud/bump on the side of the starter, and that lever also moved the bendix forward into the flywheel. as the lever moved to the end of it's travel it would close a contact switch which then made the motor get power and start to turn. that is why they had the starter relay on the fender, no solenoid on the starter. the starters with the solenoid on the starter are made to have the battery cable connected directly to the solenoid. some, like older chevy's, also use that terminal to connect power to the rest of the system and have fusible links in the circuit shortly after that connection. newer style wiring, with the fuse/relay box under the hood, would simply run the battery wire to the starter solenoid and also run a batter wire to the fuse/relay box which would house the jumbo fuses and/or the plug in fusible links. from there circuits would run into the under dash fuse box for circuits inside the vehicle that may not require large draw protection. sometimes the inside cab fuse box is simply to fuse the signal circuits that turn on the large draw relays in the fuse/relay box under the hood. so simply put, the under dash fuse box supplies the switch in the dash or steering column for the headlights. this circuit uses small gauge wire because it is simply a signal circuit that needs to supply just enough amperage to turn on a relay in the underhood fuse/relay box. the wiring harness under the dash is smaller and more flexible because it has smaller gauge wires in it. when you turn on the headlights the signal circuit powers the relay under the hood and it turns on to switch the larger gauge wiring required to run the larger amp circuit. this circuit is protected with the appropriately sized fuses or fusible links for the draw required of the circuit and also has the appropriately sized wire. a fusible link would be used for circuits that have a large start up draw, like a heater motor, that may blow a fuse when the motor is first trying to start, after it is turning the draw is less. a regular fuse may simply blow when the motor is trying to start up. it would normally be fine once the motor is actually running. a fusible link is more of a slow burn so it can stand the quick power draw of a motor start up.
make sense? relevant? help anybody?
end of rant, lol.
https://www.autozone.com/external-en...36727_188531_0