It is in the right storage compartment behind the right (passengers side) seat.
If you have the sound amp, that's usually in the storage compartment on the left side, and it takes up about the whole compartment.
On the soft top control unit, in that compartment there is a false floor, you need to remove 2 or 3 plastic 10mm nuts to remove the false floor to gain access to the control unit.

Gilly