The AC takes the moisture out of the cabin air and that helps clear the inside of the windshield from moisture faster.
Why does your ac and heater fan turn off and on
You most likely have a bad a/c - heater controller in the dash......
the ac in the car cools, the fact you have set a higher temperature than the ambient tempereature means that the car's heater is working and so is the ac, if you wish to heat up your car, turn the ac off.
There is only one thing you can do if your Heater in your car is not working. You will have to take it to the dealership and have them look at it.
Possible that the ac compressor is locking up.
so when your using the heater it show how your engine is and if its on red turn on the ac fast or your car will over heat and stuff will melt
First place to look is the thermostat
The ac pump may be seized up.
Make sure the heater is not on, sometimes the door in the heater/ac box is not working properly or the valve controlloing the hot water to the heater is not stopping the flow. An ac will not out perform a heater. The last thing it could be is that the evaporator is freezing up, or there is a clog in the line somewhere.
Some vehicles automatically turn on the a/c when you turn on the defroster. A/C removes humidity from the air and allows the defroster to clear the windows faster.
Heater core leak, or stopped up condenser drain line.
turn the car on