AC/heat actuator doors

I just purchased a used Sahara. Bought in Virginia, drove back to home in West Virginia. AC worked perfectly during test drive, all the way home until I got about a mile from home. Everything suddenly switched to air from defrost and floor only. Have checked the vacuum hoses and found nothing. Also, I am told that if the cruise control works, the vacuum is fine. Is that true? My cruise control does work. I am trying to find out where the actuators are located as the diagrams I find do not give a good location. Behind the glove box is nothing but the fresh air actuator and some color coded vacuum lines. Should I be checking at the vacuum reservoir anyway? Thanks!