Heating and AC question
I bought a 2008 Denali and I noticed I have a three position switch (AC Off Heat). No auto setting so if itís warm during the day and cold at night is to set the switch to the correct environment at that time. No auto switch over. I have a picture of a 2 thermostats. The top one seems to do nothing. The lower one seems to control the heat and AC temp. Can someone tell me what Iím looking at? Is there a way to convert thermostat to have an auto setting? I hope the picture shows up. Iím new at this.