2007 Toyota Yaris blowing cold air for 1 min then starts blowing hot/warm air

Did you replace orifice tube?

bad a/c
there are like 10 checks.
#1 is the compressor clutch de-energizing , at hot blow moment.
bingo more tests. ask

Low of freon, have it charged to proper lvls with CORRECT freon/refridgerant

see this steps and think with clearly and logically NOT feared. God bless you
Start with the compressor. Does it engage when you turn on the A/C?
If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is locked up and you need a new compressor.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged.

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

What do you mean when you say it wont shut off? is it blowing hot air or do you just feel a lite flow of hot air even if you have the settings to cold?

If this is the problem that you always feel hot air at low flow and the ac goes to hot air then i would say one of two things, first if you have the selector to cold and you feel hot air then there may be a problem with the blend door, this door move to allow hot or cold air, the door may be broken or just a bad motor that controls it. keep in mind if the ac system shuts down for any reason the air then will be warm, it will be about the same temp as outside and maybe a little hotter.

this problem almost sounds like the ac compressor shuts off and then you are getting the outside air which is hot, there are many reasons for the compressor to shut off, it could be the compressor clutch heating up and disengaging , this would be due to a bad compressor clutch.

another reason is the fans are not working, the best thing to do is when the system starts to blow warm check and see if the compressor is running, start engine and look at the front of compressor, with ac off the front of it will not move, and then with ac on the front will spin, check it out and let me know, if it blows warm air and ac is not working then it may be compressor problem but if you are getting warm air and the compressor is spinning then it may be a door problem.

This is hard to check with out testing the system, so i listed a few things to check and let me know the out come. also the ac blows cold for how long before it gets hot air blowing out of the vents, good day.

Is the compressor cutting out? It could be the compressor clutch relay is going bad.

NO,
replace the compressor only with an original Toyota part from the company Nippondenso only....
everything else is junk....
better change this silly mechanic...

I would check the following possibilities:
1. Is compressor clutch working? - You need to do this when the ac is blowing hot air only - locate compressor drive pulley on engine - rubber belt wraps around it. Start engine and set to max ac. When the ac is blowing hot air, look at the center of the compressor drive pulley using a good flash light - watch it for a while, it should be spinning with the pulley - this means the compressor is engaged. If not, the compressor is not engaged. If your ac is blowing hot air, then the compressor should be engaged and running (trying to cool). If it is not engaged, then your compressor clutch is probably going out. Could be low voltage to clutch, but more likely the clutch is worn out and only working some of the time. Note: if working normally, the compressor clutch will engage and disengage in cycles- but the air should always be cold. If clutch is bad, compressor would need to be replaced (sold as one unit). This is tricky to diagnose and could take some time - you need to do it when ac is blowing hot air but set to max cooling.

2. Low on refrigerant or refrigerant has moisture in it? If your ac blows cold initially after being off for a while, then heats up, and continues to regularly cycle back and forth between hot and cool air, then the system may be low on refrigerant or the refrigerant may have moisture in it that is freezing and restricting refrigerant flow. An a/c shop can check refrigerant level and even replace refrigerant if moisture is suspected.

Could be other issues, but I would start with these.

Good luck

is the engine warmed up,yet?>? if not you shouldt run the engine for a while and then run the heater.
you coukd have a faulty thermostat if that doesnt do the trick...