If it is broken.
It could be a faulty temperature blend door actuator.
Because it's not a heater.
You will hear air circulating in the cold air return (or return air grille) when the heater or air conditioner is running.
gas leak or wrong wiring
You are low on coolant to the heater core.
Of course, set the heater/air conditioner temperature control to cold.
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
The heater may not be on - but the fan still blows air through the vents when they're open !
The air conditioner or heater continually runs.
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
One cause of a cars air conditioning to brake is the temperature of the air conditioner. Using to much cold air at a certain amount of time can damage your air conditioner.
the answer is air conditioner
The max is 90 the minimum you can set it for is 45.