Air conditioning will expel heat to the outside when cooling. On the heat cycle the reverse is evident
An air conditioner blows out heat
Portable air conditioner will not blow cold air. What to do?
If it does blow just not cold air you should see if it needs to be recharged
gas leak or wrong wiring
you would need to add freon
diagram for 1999 chev subarban air conditioner
Coming out of the vents around 43 degrees
You have to get it recharged. you have no freeon left which makes the cold air
straight from the vent should be around 47 degrees
There are several causes that an air conditioner is only blowing cold air for a short period of time then only blow hot air and then not going back to cold. This is especially common in the hotter weather including in the 90s and above. It could be from the air conditioner freezing over. You can fix this by simple trouble shooting and if that doesn't work call a repair man.
Because that's the way there made to blow hot airbecause it's not like a heater and it's not like something that makes it cold it blows any kind of air .
You are low on coolant to the heater core.