The air conditioner alternates between AC & Heat

What is your question?

The AC was blowing ice cold with the fan on 4. When I lowered the speed to 3, hot heat started blowing out of the vents. I put is back on 4 and the AC worked again. This eve, heat was coming out of the driver vent and AC out of the passenger vent. I lowered the fan to 2 and it started blowing cold air. I noticed the snowflake on the AC button was periodically flashing red in various places on the snowflake. Any idea what this means?