The loose red wire is the hot wire for the middle single coil. If you turn the switch around to the side where the VLX91 is engraved, there should be three lugs that are connected where the red wire must be soldered. And the common lug has to go to hot. (ie volume pot output)
PS! it doesn't matter which side you solder on this switch, all the four rows of lugs works the same way, so if it happens that your guitar is soldered mainly on the side that says otax, another on could easily be on the VLX side.
on the Ibanez switch the "0" is replaced with a "C" which means common.
So if you want to know more of what does what on your guitar.
Look at the picture.
The upper left red wire is the hot for the bridge humbucker and has to be wired to the two lugs. 4&5
Then the next red wire is the hot for the neck humbucker which has to go to lugs 1&2
Common goes to hot (output for volume pot)
The white wires on lugs 2&4 on the right side, are the humbucker split wires.
That's why you see the common goes to ground.
Therefore you will need to solder the red wire for the middle single coil on the other side of the switch. So you can get the sound of a single coil in position three, and along with the humbuckers in position 2&4.
Since you're now schooled, Look at the Ibanez wiring diagram, can you find what's missing on the wiring?