ac working all the time

1999 s-10 blazer the ac is working all the time even if I put the selector switch on the hot position I still can hear the ac compresor going on and off, please help me .

your a/c control head might be faulty or your refrigerent is low on charge.

Don't keep the control on the defrost position, it goes through the AC system to dehumidify the air.

Never use defrost unless you have to , always use the floor option. Using defrost will hurt your fuel economy just like running the AC.