One problem related to windshield has been reported for the 1999 Mercury Mountaineer. The most recently reported issues are listed below.
This is a design problem. The defroster even on highest heat and fan setting, along with the wipers on highest speed, cannot keep the windshield from freezing up at any/all speeds when snow is falling on the vehicle. The driver must stop every few miles and clear off the windshield, especially the passenger side, or else the windshield wipers stop working (jammed by the ice on the windshield). It is clearly a major safefy defect in the 1999 Mercury Mountaineer when driven in the snow.