1996 Chrysler Concorde Chrysler Concord ATC control

Heater problem
1996 Chrysler Concorde 6 cyl Two Wheel Drive Automatic

My wife's ac/heater has not been performing since late this summer. The ac only gets cold at random times, and the heater only get hot at random times. When it does work, it seems to be on high. I had water pump problems and replaced that and the thermostat. I have also performed a diagnostic test on the atc system. No codes were present. I then performed a code test on the car with my obd code reader. Still no codes were present. I have also tested the in car ambient control fan/sensor. It holds the tissue in place. Finally, the only thing I notice is that when I hit the auto button to engage the atc, it flashes a couple of times and goes out. When I worked, it would stay lit up.