Five problems related to defogger controls have been reported for the 1998 Ford Explorer. The most recently reported issues are listed below.
Blend door motor failed permitting only hot air to enter vehicle.
I purchased my 1998 Ford Explorer limited from my mother in January of 2006 with 68000 miles on the odometer. In feburary I first noticed vehicle was unable to defrost the front windshield and defog the vehicles windows. The cause of the problem was the climate control would sometimes not blow warm air. This would also result in a very cold interior. After researching the problem on the internet I found many complaints regarding the 1996-1998 Ford Explorer and a common problem with the climate control's air blending door breaking, making it impossible to regulate heat and cold. The vehicle was parked until I could determine if this was in fact the issue I was having. I had no choice but to park the vehicle until I was sure I had no need to operate the climate control. I was instructed how to check for a broken blend door and indeed found mine to be broken. I took the vehicle to a local Ford dealer in carson city nevada and was told that despite the frequency of this problem it was not a recall issue and without a warranty the cost for repair was $1100. I was also informed the broken parts were being replaced with parts constructed of improved material (nylon) because of their tendency to break using the previous material (abs plastic). I feel Ford is well aware of this hazardous problem but because of the cost, won't issue a recall or even a technical service bulletin. Instead the leave the consumer to cough up the labor and parts cost to repair something that should be the responsibility of a reputable automobile manufacturer.
Temperature control system locked in cold ac mode. System will only blow cold air due to a broken air blend door. Driver can not defrost windshield with cold air conditioned defrost. I believe this is a safety issue for the driver. The problem has not been fixed because the cost will be $1200.
Blend door broken on 98 Ford Explorer. This caused the heating and cooling in the engine to be stuck in the "cold" position throughout winter. While driving in winter, I had to look out the freezing cold window to drive because the defroster in my windsheild would not heat the window.
Heater/defroster control is no longer working. Took vehicle to dealer, and informed consumer that heater box needed to be replaced.