Your ac may have lost it's freon, the compressor or condensor may need replaced, or even a small inexpensive electrical part may have gone bad - but the 1st and least expensive thing to do is to check your filter in your intake vent inside your home - if it is dirty and clogged it will cause the compressor to "freeze' up and not allow the operation of cold air. Check this 1st. If it's dirty - change it - shut down your ac for a half hour or so (for the unit to defrost), and try start up again. If that does not work watch this site for a professional or call a repairman......z8c5w
gas leak or wrong wiring
An air conditioner blows out heat
Portable air conditioner will not blow cold air. What to do?
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.
If it does blow just not cold air you should see if it needs to be recharged
The system can be low on refrigerant
diagram for 1999 chev subarban air conditioner
you would need to add freon
You have to get it recharged. you have no freeon left which makes the cold air
You are low on coolant to the heater core.
Coming out of the vents around 43 degrees
THE CAUSE for this is that when your cold air is on the petrol is used to create air. and that is how cars create cold air