Two problems related to defogger heater have been reported for the 1998 Jeep Grand Cherokee. The most recently reported issues are listed below.
Defected parts/failure: heater coil defected- blows out cold air in winter. Evaporater coil defected- a/c blows out hot air in summer.
Dealer sold vehicle with leaking rear seals, defective differential. Noticed bumping and whining noise less than 8 hours after purchase. Sun roof leaked causing the headliner to detach from roof of vehicle. Repaired once-said drain tubes were routed properly. Second time replaced roof-said seals did not match. Rear differential replaced. But did not address leakage around transfer case, seals etc in Dec 98. Now it's in the shop again! gas gauge fluctuates to empty when idling. Transmission slips. Driver seat automatiically reclines and heater does not work consistently.