Ac starts blowing hot air after a short time

Vacuum leak most likely, thus not operating air blend door.

Check to see if the radiator fan is coming on & the AC fan comes on when the AC is turned on. AC Freon may be low too.

Are you sure the relay isn't getting weak? Try swapping with another.

your ac compressor is freezing up try not putting it on cold all the way. put thermostat towards the red jus a lil but still on the cold side to see if that helps

the blend motor on the vehicle is probably bad

your ac is freezing up try replacing the expansion valve

this is because you have a bad switch which has gone bad and you need to replace it or either try to bypass it through another circuit.

try driving around for almost 4 months and the damn thing wont blow cold. try spending thousands of dollars and it still being broken. and trying driving in florida in upwards 115 degrees with no cold ac everyday. you only have to wait 30 minutes? count yourself lucky!

You have dual zones that are controlled by temperature actuators the passenger side has lost its memory or has gone bad you can put it in self programming by disconnecting the battery for ten minutes then hook it back up start the truck turn the temperature control on but do not touch any other controls let it go thru the self programming for about 6 to 7 minutes then select your temperature you want if it still does not work properly you may have a bad actuator or a bad connection at the actuator

Turn your AC off. Turn the car off Crank the car turn ac on drivers side to 60 passenger side to 90 press auto wait 1 minute turn AC off (very important) turn car off turn car back on switch driver's side 90 passenger 60 press auto wait one minute turn AC off( very important) turn car off turn car on AC 70 both sides press auto your ac should be blowing cold If not, you have an expensive problem