AC problem

The ac will always work better the faster the vehicle moves strictly based on the fact that it runs off of the drive belt. The drive belt spins faster the the vehicle moves faster causing the ac compressor pulley to spin faster. When you slow down or idle, the opposite happens. Everything slows down and the ac compressor doesn't move as fast. I would bring the vehicle to an AC professional to check the pressures to see if you are low on refrigerant and to ensure that you don't have any leaks. If everything checks out fine, it may be a defective ac compressor. Also note that if a vehicle is overheating, the computer will shut down the ac compressor if its on in order to decrease the load thats being out on the engine. Make sure the coolant level is good and there are no leaks as well. Best of luck.

Put on the engine*