I had the same symptoms; no cold air, compressor not engaging, radiator and a/c fans not kicking in.
At first, I checked all a/c electrical components(relay and fuse) and they were fine. Next, I opened up the cap on the low side and pushed the valve to see if it had any pressure. Sure enough the pressure was low.
Drove to a shop to have a/c system vaccumn and charged. The technician confirmed the pressure was low. All he had to do was apply a little pressure and the a/c kicked in.
The a/c has a pressure sensor on the high side. It's a clever fail safe device. It won't let the compressor turn on if the pressure is low or if it's too high. This sensor will save the compressor from burning out if the system is low on freon and oil.