I would highly recommend buying the plastic childproof outlet plugs that insert into the wall outlets.
Wall to stop light but not air.
If there isn t any insulation around it then mystery is solved.
Cold air moves into the room from the cold wall because the room is warmer.
When the light comes in from the sides of your drapes using velcro to hold the drape against the wall will prevent any light from coming through.
Turn off the central power to your home.
For the wall outlets there is a very easy solution.
Or perhaps some sort of tension structure.
Solution ensure the unit is on hard level and stable surface.
Unscrew the face plate and look at the hole in the wall.
As an extreme example a partial room divider could work.
Apply 2 or 3 small velcro strips to your drape and the wall on both sides of the window.
Installing switch and outlet insulating sealers is the easiest and most cost effective diy weatherization project.
Solution ensure the wall outlet can support the required power consumption of the air conditioner and is not connected to an extension cord.
Allow it to air dry.
Keep the cold air from coming in through your electrical outlets.
Wash the filter with warm soapy water.
Remove the cover of all the electrical outlets that are on outside walls.
Possible cause the unit is tilted or not leveled.
In some through the wall and ductless systems you may have to remove the front panel to access the filter.
If there is a problem with the control board it might not stop providing power to the compressor.
The air conditioner is leaking.
Even though there is insulation in the walls it won t necessarily stop the air from entering your house when the wind is blowing.
The room will not be dark but by blocking out direct sunlight while leaving openings for air flow you will be able to see your screens and still get some air flow though much reduced from wide open windows.
If you have blackout drapes but the sunlight still comes through on the sides of your drapes use velcro strips.