If your Jeep is a '97 on model and the key won't turn, spray some WD40 into the losk and jiggle the key in and out a few times. If it still won't turn, put the key in and tap it on the end with a small hammer. Once you have unlocked it, fine, but it will happen again at some inconvenient moment. Drve it to a dealer and get them to change the lock barrel. It's about £50 plus labour, it should take no more than an hour and they will build up a lock to fit your existing key. Alternatively, assuming you have got it unlocked, remove the steering column cowl, turn the key to the run position, depress the small release button on the ignition lock/steering column casting, and pull the lock barrel out with the key. You can then operate the ignition switch with a large screwdriver. Take the lock to a dealer and they will build you a copy. Shove the new one in. Job's a good'un.
