I have an central air and heating unit and I have it on out side but there is little to no air coming through on the inside and everything is all together underneith the trailor but I can't get any air coming in on the inside there's nothing on the inside but the unit is on outside I would like to know if there some defusers underneith the trailer and what to look for and how do I turn them on and off I have air in the back of the trailer but nothing in the front of the trailer and if the blower in the unit itself is working or so fourthit is my first time and I'm trying to make sure there is heat in the trailer before winter even though it is almost here it would be a great present to my girlfriend and her mother sincery matt kay