A/C starts out very cold but soon fades to no cooling at all. Refrigerant levels are good. Occasionally air will stay cold for several days at a time (2-3) I live in Arizona HELP!
check your air cabin filter or fresh air filter. if this is plugged it could cause the evap core to freeze solid and will restrict air flow and you will only feel warm air. it also could be a faulty thermostatic switch. this is usually a small square box with two wires on one side and a flexable metal tube on the other. this tube is a type of thermometer that tell the thermoswitch to shut off the compressor. this is located on or in the Evap core which is useually located underneathe the passengerside dashboard. if you have not ever taken of a dash ask around and see if someone you know has. they can be pretty intemidating.
There are several possible problems. The evaporator could be freezing, as 07tundra suggests, or the blend door in the HVAC system could be faulty. The blend door controls air temperature by directing incoming (or recirculated) air through the evaporator or the heater core, depending on the desired temperature.
If the air is not flowing through the evaporator it won’t get cold.
When the AC fades does the airflow through the vents feel strong, or does it fade too?
The airflow through the vents stays strong
Failing A/C relay or compressor pressure switch?