2006 Volvo Air Conditioning Problem...

Hey gang, I have a quick question. Does anyone know how to turn on the air conditioning in a 2006 Volvo? Is there a way to keep it running all night without turning the key and leaving the engine going? We have tried to turn on the sensors in the bunk. The fan button's light above it is red. We hit the sleeper button for the cab on the main dash, which does kick it on. But, we can't get it to run without keeping the key turned....which, we are afraid, will drain the battery. This vehicle is new to us (first day in it), and we have never run a Volvo. Little help?? We don't see a tripac on this bird...

 

That is what we figured, unfortunately....but had hopes for otherwise. Thanks, though...