What is happening is hot air coming out of driver & passenger side ports, while cold air is coming out of the center ports. Could it be vacuum check valve for climate control. Any advise would be appreciated.
Thank you

sounds like heater valve, mono or later duo-valve leaking , when not commanded , hot coolant maybe coming thru, to test pinch th heater valve hose and see if heat stops coming out sides , if it does , check for electrical operation , if that checks ok replace valve as rubber seal internally are probably torn

Thank you Nulu