First a quick Pet peeve of mine
The words relay and solenoid are often used interchangeably and I can't change that, lol, but I try
A "relay" is used to pass electricity on, to activate an electrical device
A "solenoid" is used to cause movement, like pushing out starter gear or popping a ball out on a pinball machine
They both work the same, low amp coil of wire when powered becomes electro-magnet and causes electrical contacts to close(relay) or an arm to push out or pull in(solenoid).
So there is movement in both, lol, my dilemma
Here are some images of starter motors
Starter with solenoid but no internal Relay: http://autosystempro.com/wp-content/...rter-motor.jpg
Only 1 wire runs to this, the battery cable from starter relay on the fender, it is grounded via it's bolts to engine/bellhousing
When it gets 12volts on the one wire the Solenoid pulls in the rod which pushes out the starter gear
AND when the solenoid rod pulls in its "contact plate" connects Battery Cable terminal to Starter motor terminal, activating starter motor
So this is actually a solenoid/"relay" because it does both movement and passes electricity to activate a device
This is image of current starter motors with separate, but internal, Relay and solenoid: https://images-na.ssl-images-amazon....1L._SX355_.jpg
With these the positive battery cable runs directly to the starter motor(larger post on motor), no fender mounted relay needed.
The smaller post is the "S" wire connection, the wire from the ignition switch that has 12volts when key is turned to START.
The "S" post activates the Relay part which then activates the solenoid and starter motor.
During the transition to this type of starter there was often a fender mount "relay" but wasn't used as a relay, it was used as a power distribution post, to hookup alternator, fuse box and other electrics until newer wiring harnesses were ready.
And then a "starter relay" was put in the engine fuse box, this was part of theft prevention system, the starter motor was still connected directly to the battery but the "S" terminal got it's 12volts from the "starter relay" in the fuse box, this relay was activated by the Key in START position.
But this relay wouldn't work unless alarm was deactivated, either PATS or Ford alarm, so no crank.