To find it, you'll likely need to:
1. Locate the fuse box: This is usually under the dashboard on the driver's side.
2. Look for a small relay: The flasher relay is a small, square or rectangular component. It might be labeled, but often isn't. It's usually among other relays.
3. Consult your owner's manual: This is the best resource for the exact location in your specific Jeep. A wiring diagram will be even more helpful.
If you can't find it easily by visual inspection, using a multimeter to test relays in the area might help identify the flasher. (Remember to disconnect the battery's negative terminal before doing any electrical work.)