Heat pumps are part of A/C system, they would discharge air in same registers as A/C, how long have you had this coach, could be you do not have heat pumps and some one changed wiring. Another possibility is someone replaced your original a/c units and did not opt for a/c, heat pump type units, at that time changed wiring for furnace. Your a/c unit model and serial number should tell you if units have heat pump capabilities.
2002 Monaco Executive 500 ISM
2004 GMC 2500HD 4X4