you sound like you are pretty convinced that the Brand New board is bad (that would be pretty unusual). Maybe we should go back a couple of steps and check some basic items. First lets check the condensor fan itself for freedom of movement, do a push test to see if it starts, if it starts with push test replace the capacitor. Now if still no luck lets checkback thru the power circuit for proper voltage check/replace the run capacitor for fan motor. Now lets double check for proper call from thermostat for cooling (usually best to bypass the thermostat to check it) if all is good there we really need to take a close look at the new board and relay to be sure it is wired correctly. Note: most of the time in commercial buildings in the winter time outside air can be used to cool the interior instead of running the AC system. Most Trane commercial units have options for outside air intake and ambient controls not sure wat you have there as far as the model but may be worth a check.

Hi. Thanks for replay.
The outdoor fan is fine and spins on its own with out any assistance when jump wired across the 1-2 terminal on the defrost relay which is for unknown reason energized in cooling mode. It should be off in cooling mode where those contact are closed in normal position for the fan to come on. I measured 24 volts on the coil of the defrost relay which is mystery while I am in cooling mode. That 24 voltage should be present only in defrost mode for faster deicing when the outdoor fan is cutoff of power. I removed the wire to the defrost relay so the outdoor fan can run and I disabled the heat switch on the thermostat for the rest of the winter. The unit works fine with the defrost relay disabled. Once I connect the defrost relay back the outdoor fan can't get the juice due to the opened contacts on the defrost relay. As I mentioned it's energized by the defrost board in cooling mode and that is strange for new board unless some external element like thermistor would activate it but it shouldn't be in cooling mode I guess. Now the issue is about the heating for the next winter. I have all 220/24 voltages correct. It was working fine for one week including the heating but I am going to give them call again just to make sure. The unit was working in both heat and cooling when I was leaving, I doublechecked that before I left since it takes me 45 minutes to get there with my 5.8L engine these days. We don't use the outside air to cool inside and they called me back that the cooling doesn't work and there I discovered the mystery. The unit is made in 1978. The unit comes on when thermostat calls for cooling but the outdoor fan is disabled by the energized defrost relay. Thanks again.

In order for the defrost cycle to start, the condenser coil sensor has to be made, this happens at 28 degrees. Also the defrost timer clock has to complete it's cycle, this depends on the setting, could be 30, 60 or 90 minutes. Both the timer circuit and the temperature sensor on the cond. coil has got to be made before the defrost cycle can start. If either is not made, they will not be a defrost cycle start. If your wiring is correct to the board and from the thermostat, and if in fact it did work correctly for the first week in both heating and cooling modes, then it may be the board. This isn't common for a new board but is not unheard off either. Or else you have a wiring problem or multible problems that will require further investigation. If the unit has aux. heat, if the unit is in a true state of defrost, it should also turn on the aux. heat, whether electric strip or whatever.