1998 Plymouth Voyager NO heat

Hello, I have a 98 Plymouth Grand Voyager during the summer the battery drained low but after a charge did not need replacing. The lights on the heater/AC control panel flashed and I was able to run the recalibration but the end result was no heat from the dash when set to any of the heat options. When the calibration is run though Heat does come through the dash when it cycles through all the settings. Once the calibration is run though the top button flashes once then the button directly below flashes 3 times, this does not stop until I hit the top button. Please help