The fans are not designed to come on every time the A/C comes on. They only come on if the coolant temperature and/or A/C pressure exceed certain values. The coolant temperature values are different for A/C operation. There is a high-speed and a low-speed fan that come on separately as needed.

If having the driver control the fans with a switch was a good idea it would have been designed into the car. You don't want to be constantly looking at the temp gauge. Your eyes should be on the road. There's a computer to monitor that constantly.

 

Alright, I read your first post but it wasn't very detailed, reading this comment clears it up a bit, thanks.

I agree but unfortunately my vehicle doesn't have a temperature gauge so the only way of knowing I am overheating is when the light comes on a dings repeatedly and steam is pouring out from under the hood.
I know this from experience.

Can you explain the purpose of the ambient temperature sensor on the front of the radiator and what it signals to the PCM and what the PCM uses it for ?

 

The ambient temperature sensor measure the temperature of the outside air. The PCM uses that information for fuel management, much like, in the old days, there was an automatic choke in the carburetor that ran a richer mixture in cold weather until the engine warmed up. If your car has an external temperature readout inside the car, it is getting its information from that source as well.

 

This, here. Going with the switch would be absolute, last ditch, it needs to work bush fix. Sensors are annoying as all hell, though, so I can understand the appeal of a switch and being done with it.