Why would auto air conditioning blow cold air at startup and then blow warm air quickly?

2003 Ford Explorer Limited V8

Needs a recharge, if not afraid you have a leak

Cooling fan not working

The evaporator may have water over it and that would freeze up. This eliminates the cooling ability of the system. If you can, locate the cabin air filter and check that. You should also check the drain for the evaporator housing for a blockage.

Thermostat is stuck open. The computer shuts off the A/C.