No cold air

Make sure the setting on the remote is correct . Sun symbol for heating. Make sure the filters are clean. On heating, the indoor unit will 1/2 open the flap but the fan shouldn't start. The outdoor unit should start and if working properly, will be blowing cold air. The indoor unit will open the flap fully and the indoor fan will start once it gets hot then you should feel warm air. If the outdoor unit is blowing warmish air, I would say the reversing valve coil has failed or one of the indoor temp or pipe sensors are faulty. If a sensor fails, a "CH" error should appear on the display.

THE OUTSIDE FAN MOTOR MIGHT NOT BE WORKING CAUSING THE COMPRESSOR TO GET HOT AND TRIP THE INTERNAL OVERLOAD IN THE COMPRESSOR - IF THE UNIT IS LOW IN FREON SAME RESULTS - WHEN UNIT IS FIRST TURNED ON DOES IT BLOW COLD AIR OR DOES THE AIR NOR FEEL COOL - JUST COOL AIR COULD BE LOW FREON - COLD THEN WARMS UP IS FAN PROBLEM

Heat pumps defrost which is the AC mode, if the heat strip isnt working during a defrost, the air will be cold, A heat pump only feels warm if the heat strips are on too! the refrigeration cycles heat output is much less sensible to our 98F skin. heat pumps that satisfy a room setpoint are working at least, all heat pumps feel drafty to most.

It may be frozen over. At the front of the unit there should be an air filter. May be behind a panel that opens, or it may slide out. Behind that filter will be the indoor coil or evaporator coil. Look to see that coil and if there is any ice on it. It will be a white ice covering the coil. If it's frozen up, turn the cooling mode to off, turn the fan mode to on, and let it run at least a couple of hours to thaw. Let maint. know it's frozen up and needs service. Get what you pay for! If it's not frozen up, find some way to check the supply air temp. Some sort of a thermometer. It should have a 50-60°f supply air temp, depending on the indoor temp. Most I've seen will supply 45°f, but 50-60 is a good reference. Hope this helps! I bet it's frozen up.

Cooling fans working? If you notice the air getting warm mostly while stopped, probaby cooling fans not turning on. if the fans are working properly, may be low on freon and need a recharge.

The fridge gets its cold air from the freezer through a vent(damper) between the freezer and fridge.The fan in the freezer blows air through it. There is a flap you adjust with the fridge temp. control. Make sure it's opening and closing when you adjust the fridge temp.

If after freeing the fan blade it still will not turn, you have a bad fan motor. (almost certainly due to it being restricted.)

That will cetrtainly cause it not to cool properly.

If the fan will not turn after freeing it, it will need to be replaced. If it does turn properly, unplug the fridge for about an hour to let the compressor cool down. Make sure all the coils vents etc are free of dust and dirt. Plug it back in, and if the fan is still operating properly, you should be back down to temp in a few hours max.

you have a slow leak in your refrigerant and need to find the leak. you will have to get an AC repairman to come to your house and check it for leaks and fix the problem.

Is the outside unit running? if so can you feel warmer than outside air blowing from outside fan? If not your system may have a leak and pressures low. You can also check the piping to and from the unit larger one should be cold small one should be warm

check outside unit large pipe should be cool or even very cold small pipe should be warm to touch that will eliminate some questions in order to solve problem also check circuit breaker for outdoor unit see if fan on outdooor unit is running and listen for compressor hum