PROBLEM WITH MY AIR CONDITIONER

Not only "is your outdoor unit running" Is your compressor in your outdoor unit runnning. I've seen people make mistakes thinking that just
because the condenser fan is running that the compressor is too. It sounds like the compressor is shutting down due to overload (hight pressure). The way to know would be to pull power to the unit, then take the door off restore power and listen to see if not only the fan turns on but the compressor also. If the compressor is very hot to the touch and is not running, again turn off power to the unit and run a hose over the compressor. for a few minutes until it is cool to the touch. Restore power and see if compressor starts. If it does the problem could be a dirty outdoor coil (clean it with a hose). If that doesn't solve it, call a tech.

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