Why whenI turn on the a/c and one side blow cold and the other side blow hot air on 1998 Buick Park Avenue

The ac blows cold on driver side and hot on passanger side why is that so..

Asked by for the 1998 Buick Park Avenue
1 answer
YOU MUST HAVE A DUAL ZONE SYSTEM , CAN BE SEVERAL THINGS , MOSTY IT IS THE HEAD UNIT, OR THE SERVO MOTERS GOIN BAD THAT CONDTROL THE BLEND DOORS.