Seven problems related to defogger heater have been reported for the 1997 Ford Explorer. The most recently reported issues are listed below.
The heater blend door failed on my 1997 Ford Explorer while driving it in snowy conditions. I only had cold air blowing on my windows. After reviewing web sites, I have found that the top piece of my heaters hot and cold blend door is broken. The cost of replacing this one piece of plastic is around $1000. Ford has a replacement part that is now stronger, but fails to realize the defect in the older doors.
1997 Ford Explorer developed a defect in the defroster and defogger system. The problem was due to a broken plastic door in the a/c/heater plenum. This created a condition of fogging the windshield uncontrollably and impairing the drivers vision.
Heater in vehicle became inoperative during a sleet and ice storm. Heater blend door failed causing only cold air to blow out of heater and defroster, windshield and windows fogged up and I could not see the road. Heater box and blend door replaced that cost me $700. 00. 8nm.
Consumer noticed when turning dials on heater unit from hot or cold the unit only blew hot air. The technician stated the heater blend door needed to be replaced.
Heater runs at full heat no mater what temperature selected.
Heater blend door on my 1997 Ford Explorer does not change positions. It is stuck in the position only giving me air conditioning full time. No matter where the dial on the dash is turned the heat refuses to activate. Through a quick series of odd weather occurrences I found my windshield covered in a layer of ice that could not be removed since the heat did not work on the defroster. This almost caused a near fatal head-on collision. I have no option now but to have the heater plenum replaced at a cost $1010.
Heater control valve also broke.