Challenging diagnosis& fix,w/pic,Ford V-10 battery light

It isn't limited to Ford vehicles. Such crimped junctions are quite common in all vehicle wire looms, and they will all eventually corrode and become high resistance connections.
But, soldering the connection or installing aircraft style terminal strips would be time consuming, and add hundreds of dollars to already over-priced vehicles.
"There is never the time or money to do it right, but there is always the time and money to do it over!"