Bunk A/C not working

ok, 2001 379 xhood A/C works great in cab and the blower works in the sleeper but no cold air. When i feel the lines going from the front to back they are not cool at all. almost like the line is plugged. is there a valve on the sleeper a/c that is electronically opened and shut that may be bad? I tried to find some kind of a A/C diagram on line for the 2001 but can't seem to find anything. What is the easiest way to get to the coil? if i go through the side box it just exposes the back but nothing that could go wrong in that area. any help with this would be appreciated. we're attempting a restoration as we are running the truck and in need of the a/c.