Heater issue

[Dibly74]

My 79 Continental has an iffy heater. Sometime it blows semi warm and other times its completely room temperature. Also the "Heat" selection turns the fan off completely. There is a vacuum hose under the dash the will make it blow hot if I unplug it. I already took the dash off to make sure the hot/cold secector was acually putting it on hot. The guy I bought it from said when the AC worked so did the heat. But when the AC blew a hose the heat quit working. Is there a bad relay, bad AC controls, or what.

[Dibly74]

Just thought I would finish up on this problem. I replaced whats called the "sniffer" for the AC controls. Its under the dash with two vacuum lines going into it and has the hot cold selector attached to it. Fixed my problem immeditally.