air conditioner

I believe there is a heater control valve at the rear of the engine compartment make sure the cable attached to it is operating the heater valve correctly allowing the valve to be fully opened and closed as a friend operates the heater controls from full hot to full cold. Some cars do this using an electric motor under the dash incorporated as part of a electronic climate control system eliminating the traditional type heater control cable operated valve. Air conditioning works on high pressure only a small leak quickly causes a drop in pressure. It is often hard to locate air conditioning refrigerant leaks. There is a refrigerant that has dye in it that helps locate a leak. After recharging the air conditioning with the dye if the system leaks it leaves a stain to help locate the source of the leak. An electronic "sniffer" can also be used to locate leaks, it acts like a geiger counter as you come closer to the area of the leak the "sniffer" beeps loudly.In either either case the system will need to be evacuated have the leak repaired and recharged with refrigerant and the proper lubricant or the system may soon loose its refrigerant charge again.