Two problems related to defogger have been reported for the 1999 Mercury Cougar. The most recently reported issues are listed below.
When the heater is turned on or on a rainy day, the windshield steams up and consumer has difficulty seeing.
I have the manual transmission, and when driving below 35 mph with the defroster or air conditioner turned on a constant, surging is felt about every minute. At even slower speeds it becomes more of a concern as the car will surge unexpectedly when driving in parking lots or negotiating corners. If the defroster or air conditioner is not turned on then the car operates normal without any surging.