What causes your air conditioner to not blow cold air?

An air conditioner blows out heat

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

i have a pioneer travel trailer, air conditioner the compressor does not come on please advise is there internal switch?

A.C. circulates air(just like a fan) and turns it cool.

air conditorner doesnt blow cold air has freeon compressor doesnt kick on

There are multiple reasons why this might be, and no way to narrow it down without proper diagnosis.

Make sure the radiator fan is turning on when the AC is running.

First determine the symptoms the air conditioner is having. For example, does it have power, is the fan running but no cold air, is the cold air not cold enough? Then you can look up possible causes on the web in sites like http://www.repairclinic.com/Air-Conditioner-Troubleshooting?red=Air-Conditioner-Repair-Help