After the link blows, what stops working? Does the engine still crank? If it does, the terminal on the starter relay is just a convenient tie point. Ford is famous for doing that, but your car should have plug-in relays with no provision to bolt on extra wires. For that reason, I'm guessing the link is in the starter solenoid circuit. It should not blow when the circuit is not energized.
If the link blows while driving, (not when cranking the engine), use plug-in terminals and / or clip leads to connect a headlamp bulb in place of the fuse, then wiggle and poke stuff to see if the short will occur. When it does, the bulb will go to normal, full brightness. When the short is gone, the bulb will go out. That will save the expense of constantly replacing fuses. If this is indeed the starter solenoid circuit, it will not work with the bulb installed because the bulb has too much resistance to allow enough current to pass.
A more common high current circuit to cause this problem is the radiator fan. If the link doesn't blow until the engine is warmed up, and you suspect the fan motor, bypass the fan relay and watch if the light bulb gets bright. If it does, unplug the motor and try it again. If the bulb still gets bright, there's a short in the wiring. If the bulb stays off, suspect a shorted or tight motor. If the motor tries to run, it will run slow due to the resistance of the light bulb in the circuit.
To bypass the relay, unplug it and use a jumper wire between the two terminals for the relay's contacts as shown on the drawing in the side of the cover, OR, you can pop the cover off, plug the relay back into the socket, and squeeze the contacts to turn them on.
Other things to try include rocking the car while it's in park to cause the engine to rock. This will make wiring harnesses shift position. If you can get the light bulb to stay bright, run around unplugging various connectors to see if any affect the bulb. That could help lead to the cause.
Monday, January 25th, 2021 AT 7:48 PM