Hi, I'm new to the forum. My 2005 Fleetwood Prowler with Coleman A/C has a large central ceiling air conditioning register divided, with an outlet filter where air flows out very forcefully and cold and a larger half that appears to be a location for an optional ceiling heater and no air moves in or out from this louvered side. There are two other smaller ceiling registers in the main room, one in the bedroom and one in the bathroom. I have a gas furnace with floor registers. With the fan on high I can only feel a slight breeze from the aft room and bathroom ceiling registers. There is NO flow from the front and bedroom registers. Behind the filter and downstream of the fan there are 2 openings that channel air to the forward or aft registers. I cannot see what is upstream of the fan. I have tried blocking the filter to see if more air will go to the registers but it only increases slightly to the rear two. Where is the air entering the system? Why is blowing OUT through the filter? Does anybody have a solution? I find it strange there is a filter in the outlet rather than the return. Maybe this is just a poor design for channeling air.