My 2002 e350 van has a cut wire on the positive battery terminal. I assume it is a ground wire. Should there be one attached to somewhere? For what purpose would someone cut it? What problems might be inherent to it not being there?

 

Whoa !!
Whatever you do do not attempt to connect that wire at the positive battery cable terminal to any ground ! Guaranteed to lite up your life. Either battery positive or battery negative , but those two connections never get connected to one another without some type of load in between. The full charge in the battery will try to equalize rapidly if any provision is made to allow a "short circuit". without some type of load in between. A load can be a light bulb, motor, or any electrical appliance radio ,blower etc. The wire must have at one time been used to provide the positive side of a circuit ,load, and the other side of the load went to ground.
There was a heavy gauge red wire that ran from the alternator to a junction on the left fender well under the hood. From there the wire went to the battery . It was used to provide a path for the charging system to charge the battery. Maybe someone decided to change that . Check to see if that set up is still present.

 

Ok, I'll look. But my battery charges just fine, so would that mean it is there? Or is the wire you're talking about something else than what is required to charge the battery? Something extra?