I have a 1995 Nissan Quest with 260K miles. In the last month, I have been having a recurrent problem with it. Basically, every time I switch on the AC (front panel), it works fine for about 20 minutes (good, cold air flow), then gradually the airflow coming through the vents decreases gradually to a level when it can hardly be felt, even when it is turned up to the max. When I place my hand in front of the vent, I can feel the cold air coming out, but little. At this point, inside the car, no effect of the AC is felt. When the car is parked for a couple of hours, then the AC works again, but after another 20-30 min, the whole thing is repeated.
I would be grateful for any suggestions as to what is the likely problem. Is it the fan, or the AC? Do I need to take it to a Nissan garage, or any garages (Firestone etc) would be able to determine the problem. Thank you for any suggestions.