I have two of these, one controls upstairs and the other controls downstairs. The one downstairs works properly, the fan continues to run for a minute after the A/C cycles off. The one upstairs shuts the fan off immediately when the compressor cycles off. I need to program the one upstairs to keep the fan running like the one downstairs. Is this possible? I have no paperwork on these units, I think they are 1986 vintage.