Applying voltage to the "S" post on the relay will close it and send voltage to the starter. It's gonna make some sparks when touched to a pos voltage connection. Another thing you can do if you have a set of jumper is to take connect on end to the battery, blk to blk and red to red. On the other end, connect the black to the starter case and the red end to the threaded stud that goes from the relay to the starter. Sam thing, you will probably get some sparks. Be ready.
It's just a Jeep, and if you don't wheel it once in a while, it's not even that.