Electrical system goes dead

First, clean and tighten the battery cables. When you're done you must not be able to twist them by hand.

If it continues to act up, we need to keep it not working so we can troubleshoot it. Do you have a digital voltmeter and know how to use it?

Caradiodoc

Nope, a blown fuse will not heel itself later, but some circuits use an automatic resetting circuit breaker. This is common for power windows and head lights where it is important for them to try to work again for safety reasons. Those circuit breakers only protect specific circuits. Other things will still work.

Ford likes to use the starter relay as a tie point for other circuits. It's common for the soft copper nuts on that relay to work loose and cause all kinds of problems. Follow one of the red positive battery cables to that nearby relay which will be bolted to the body. Tighten the nut that cable is attached to but be very careful to not let the wrench touch anything other than that nut. If the wrench touches the body or other metal brackets, you'll have a dead short and lots of sparks. If the wrench welds itself in place, it will turn red-hot.

Also look for an under-hood fuse box. If there is a fat wire bolted to it, tighten that nut. Look for a large fuse that is bolted in. That is another one that could work loose.

If those things don't help, you'll need a voltmeter or a test light to locate the break in the circuit, and you'll have to do the testing while the problem is acting up.

Caradiodoc