I'd advise you to do what I do - when you go in to buy plugs, oil, or any other parts, look for a display of Haynes or Chiltons manuals and pick up the one that covers your make and model of Jeep. The manuals aren't all that much (unless you are a real skinflint), and if you plan on either doing a lot of work yourself, or owning the Jeep for any appreciable time, then a decent manual like those will serve you well.
From my experience they pretty much hit on everything, including the simple stuff like this.
Besides, if you don't know how to replace it, you've never done it on this vehicle, I'd almost assume it needs to be done (particularly if you just bought it). I'd pick up the manual while picking up points and whatever else you think you would need. Hell, the last manual I bought was for my GMC; I plopped it down on the counter and started asking for parts I'd thought I would need that day from the illustrations, before I even paid for it. [ Erronius's advice column | Ask Erronius A Question ]
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