I went on a short trip and everything was working fine until I was driving home and while I was driving, my ac in my 2004 VW Beetle just started to blow hot air. I turned off the car and restarted it and it is still blowing hot air.

Check that the wire to the temp sender unit has not come off and is shorting out on the head.It it is it will read as overheat on the gauge straight away

Hello,
my advise to you is that:
Your VW problem is the throttle body, (good news) it doesn't need replacement, it only needs to be cleaned out, and even better if a good technician (know what he is doing) can run an adaptation procedure.
this will restore the ZERO position for the TPS and relearn the target engine idle speed.
Good luck.
Note: you are in my prayer.

it may not start back up it needs to go to vw dealer to reset system

without putting my machine on it and extracting the gas to see how much gas their is by weight then i couldnt even think of a reason for this sorry

fuel pump , security issues, ignition issues

**** in the venturi valve ,remove the ac interior unit and clean it all out ,broken bits of the old compressor blocking the restrictor (venturi )

I have this same problem! EXACTLY. Did you ever find the problem??? Mine is 2000 Beetle.

Check the oil level to make sure you have sufficient oil in the crankcase, and that it's not burnt. Also check the level of the antifreeze/coolant in the cooling system. Low levels can cause the car to shut down. Alway look at the cheaper easy to solve problems, then move to the more complicated.

run a scan tool on it and make sure there are no codes, if there is codes address those problems first, if no codes.. next time it won't start check for fuel preasure. it is probably a fuel pump getting ready to go out or they may be a large amount of something other than gas clogging the pick-up sock at bottom of fuel pump.

Hi, check front hood micro switch at latch or radio switch for antitheft it is open.