The '98 Jeep Wrangler (TJ) and Cherokee (XJ) both were affected by poor connection at the instrument cluster. This condition may cause erratic operation of the speedometer, tachometer, and the airbag-warning light, along with setting a fault code in the Airbag Electronic Control Module. The connection problem is actually caused by oxidation at two of the male electrical terminals on the back of the instrument cluster assembly. DaimlerChrysler has come out with Technical Service Bulletin 08-20-98A, which we pulled up on the ALLDATA information system. This bulletin gives detailed instructions on removing the oxidation with the use of a scraping tool and an electrical contact cleaner. The connection is then protected by applying a specified dielectric grease. We recommend having the job done at a Jeep service department. A poor-quality repair may result in damage to the instrument cluster and/or a repeat of the original problem.