How To Work Espar Apu?

I got my first truck, 2016 t680 and couldn't be happier. But I'm dying from the heat at night. How do I turn on AC?

That's two different questions, Andrew. If you're "dying from the heat" because It's hot outside, open the windows or use the a/c blower.

The espar that I know of is only a heater. It won't turn on till the ignition is off, and you turn it on. You could set it for a low temperature, say, 68°, and it will slowly blow cooler air.

Does that answer your question?

The espar does both heater which uses fuel and no idle AC which uses the truck batteries. If I read correctly the truck should auto start in the accessories position or off to charge up the batteries

This is a video from Crete/Shaffer

Espar heater and no idle AC

And this video is from TMC they use a different style control panel for the espar. Right about :45 secs is where it shows it.

TMC incab