Air not blowing out forcefully

https://fireplacehubs.com/york-furnace-red-light-blinking-7-times/

https://upgradedhome.com/york-furnace-red-light-is-blinking/

Look for trapped air in the coolant system. When you are running down the road the engine RPM provides enough pumping action to force the coolant pass the air locks (trapped air) in the system.

You need to purge the air from the coolant. Some engines require opening a purge plug to vent.

The following video provides a simple way to remove the air.
Chevy pickup suv fill and bleed the cooling system

It sounds like your AC unit could be overheating or even damaged.

AC units have a sensor that will turn them off automatically to prevent damage from overheating. If there is an insufficient amount of air flow, the unit will heat up, and then eventually turn off.

When the car is moving, more air is forced over the unit, likely keeping it cool enough to run, however, when the car come to a stop, it loses that air flow, and quickly heats up. Thus, the AC would work while the vehicle is in motion, and overheat and stop when the car is stopped and idling.

However, the AC unit could be completely blown. The cold air while moving could be just a case of air being forced into the car. Think of a house fan, the fast the wind blows on you, the cooler it gets.... Thus, it could be an illusion that the AC is working when car is in motion, when it really isn't.

Hope this helps.

Short of gas. Time to call a technician

Do this:
When the vehicle is COLD, start it and start the a/c and see if it is cold then. If so, your heater temperature controller is stuck in the HOT position. Check the hoses going from it and if this is true, replace the controller. The a/c is running, but the controller is sending hot water to the passenger compartment heater radiator.

Gary

It could be that it is not charged correctly. Check the insulated copper
line outside if it is sweating and the condensor is discharging hot air, then the ac is doing all that it can. Check the evaporator inside to see
if the drain has condensate coming out of it.

Getting the heat out of the attic is a good idea, but you must have enough make-up air in the attic for the fan. If you do not have enough
make up air, it will start to draw air from inside the house. One way to check this is if you have a gas water heater and or furnace. If you put
a flame by the exhaust pipe in the basement and it blows it out, then you now have a backdraft problem.

Run the AC withoutthe fan, my real guess is the unit is not properly
charged or you do not have a big enough AC unit.

You may have a bad capacitor. But you may nee a service tech to check it out. There is only so far you can go without knowledge of Air Conditioning. Ask for free estimate and you will know upfront what the cost is . RUS

If you recently had any thing done with the cooling system theres more than likely an air pocket in it.Let the engine cool down and remove the coolant cap and make sure it is full ..With the cap off squeeze the lines going into the cab which are black hoses about the size of your thumbs plus a little bigger.after doing that make sure you coolant is full and put cap back on and you should have heat continuously. Even if theres wasnt any work done on the truck it still could get air pockets in it.This should help you....

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_a3369546f8067589

Putting a/c is way rediculously too costly to even attempt, also, jeep a/c back in the day was mediocre at best, just deal with it. If you wanna cap that hose line off, go to town, but id really suggest not turning on the fan (that does not blow clod air to begin with) and just putting your windows down.