03-06 used an air actuated locker - 5 PSI!
07+ use electronic actuated.
assuming you have 03-06 you'll have to get a 5-lb regulator, there's a lot of different ways you can wire it depending on what your air source is.
Oh, and word to the wise....use a few wraps of teflon tape on the threads of the fill plug on the factory covers or the stupid plugs will contact the locker actuator and lock it up for ya on the street.
Another piece of advice, use the rear sparingly...it's not a very robust locker design b/c it it uses the limited slip helical gears to lock the driver side in and they're prone to stripping out (I've already had it happen once on my 05 Rubi). The front locker does not have limited slip, so no helicals and is generally considered more robust. The front locker can be installed in the rear if desired, so if ya do strip the gears the cheapest replacement will be a factory front locker (or consider upgrading to ARB at that point).
Oh, last comment - limited slip additive is not required, the FSM incorrectly states it but you don't need it because you don't have a clutch pack limited slip, it's gear driven. Check out rubiconownersforum.com for lots more info....
