I don't think you mentioned if it was the front or back,
easy thing you can do is swap bulbs from one side to another and see if the problem follows the bulb. Sometimes it's hard to see if the filaments are good. An Ohm Meter would be a good way to check but most people don't own one or have no idea how to use one. the bulb swap is always quick and easy.
If the problem stays on the same side though, it's probably the socket itself. This is actually common for Jeeps, or at least for me it has been. The metal contacts inside the socket break for whatever reason. I've replaced both of mine on the front and now need to replace one I purchased a year ago.
I think someone with a local Jeep might have done a swap on me in a parking lot....but that's neither here nor there.
good news is a local dealership should be able to get just that socket cheap, say around 10 to 15 bucks.
You may have to go around with them cause they may and try and sell you the whole wiring harness, which is wrong.
I finally got the right person to do a little research and he found the correct part number and ordered it. he was glad too because that PN is used on several other vehicles that have the problem.