Need help please,,just got a '99 grand cherokee,1st:my rear/back door willnot lock,,how do i lock it??front 4 doors lock with master on drvrs.door& w/remote,but the very back liftgate will not,theres no external key hole,i'm confused.2nd:10disc changer,the first burnt cd i put in worked fine,,pulled mag. to put in another cd and now can't get mag to lock in,,3rd:driver side lumbar support is at highest point,pushing hard on back,,switch doesn't work,,need to release this thing somehow...Thanx