I need to replace the bedroom AC in my 2009 Bighorn 3670rl. It's different than the one in the living room and has, what I believe, it's own thermostat separate from the living room thermostat, but it doesn't seem to have any control over it. The unit just comes on at odd times and it has knobs on it that control full fan and cooling, so not really sure what the extra thermostat is used for. I'm also not sure what replacement AC I should purchase. Do I need to find something similar or do I have choices?