There is a good chance that the previous owner of your Jeep, or the Dealership, deliberately removed the LED from the Cluster to hide a constantly-ON Airbag light...instead of fixing the problem.
With ignition turned On the Airbag Light should come on for a few second and then turn OFF if the system is working.
You can also excercise all the cluster lights and the gauges by holding in the Odometer trip-reset button while turning the ignition ON....al the cluster lights....including the airbag light...should come ON and the gauges should move back and forth. If this does not happen then you need to remove the cluster, open it up and have a look at where the Airbag LED is located...probably has been pried off or it is burnt out. If this is the case you can get a replacement LED from Radio Shack and have someone solder it into place for you.
If the Airbag light is now ON permanently...you need to get codes read to see which airbag it is complaining about.