I have a used Traulsen URS-36-DT and the consenser fan does not seem to be behaving correctly. Essentially, it is always running, regardless of whether either of the compressors is running. I know this is not standard, but is it possible that it is designed that way for this unit? The other odd thing is that it only runs if both the refrigerator and freezer are switched on (at the switches, not the cold control). So I cannot turn the freezer off and have the condenser fan run for the refrigerator for instance. (Actually, I can, by turning off the freezer with the thermostat, but not with the switch). Is this wired incorrectly, or is there a part that is not working correctly?