The temperature settings on the rear vents are the same as the front vents on the same side of the vehicle. Ensure they are on heat, turned on, and are set to blow out the top (not toward the passenger's feet).
yes
check cabin filter
Your front blower motor has gone out. There is a front and a rear blower motor.
It vents directly out the side of the house n doesnt need a chimney
vacuum leak?
The air of your Chevy trailblazer 2004 blow out of the front vents when the air conditioner is on because the air condition is faulty and it needs repair.
Front heater core is in the dash, the rear heater core is all the way in the back of the vehicle. If you have steam coming out of the dash vents, the front HC is leaking. If you have steam coming out of the rear heater vents, then the rear core is leaking.
Vacuum leak
I believe the upper vents are for A/C only. The floor vents are for the Hot air. Test your ceiling controls by moving the knob from cold to hot, you should hear the air pass from upper vents to lower vents. Providing of course you have selected REAR from the front control panel.
he used the door? the question doesnt say he didnt have a door... just that he didnt have any windows or vents.
You need to check the vacuum lines for the a/c system for leaks, breaks and loose ones first.......