During the summer, your car's air conditioning can be a saving grace from humidity and the damp clothes that come with it. Sometimes when the air conditioning is turned on at the beginning of the season, nothing but hot air blows out. Knowing how to troubleshoot your car's air conditioning can keep you from showing up to work drenched head to toe.
Parts
Knowing the parts that make up the air conditioning system is integral to proper troubleshooting. The condenser sits at the front of your air conditioner and holds the coolant, or refrigerant. The condenser is connected to the evaporator through a series of hoses. When troubleshooting the air conditioning, check that the condenser has enough coolant to keep the air conditioning working. Some condensers have an automatic shutoff if there is not enough refrigerant in the system.
If you have recently filled the condenser only to find that it is drained again, check all the hoses for leaks. Refrigerant or cooling liquid is usually fluorescent green, yellow or pink. Look under the car for puddles. If there are none, run the car for a few minutes with the air conditioner running, switch off the engine and allow it to cool, then check all the hoses for liquid.
Intermittent Cooling
If the air conditioning is blowing cold air before shooting out a warm breeze, the system may be freezing. Ice can build up in the system if there is too much moisture, causing the tubing to clog. Generally, air conditioning systems should only contain 2 percent of air by weight. Cooling performance is lowered when any more air is present. Special refrigerant identifier equipment is required to test for this. This can be expensive, however, and is better performed by mechanic.
Electrical problems can also cause intermittent issues. Check that the AC control switch inside the car is working properly. If it feels loose, it may not be reading its setting properly. Also check the contacts behind the control box to make sure they are properly connected. Check the fuse box to see if any of the fuses connected with the air conditioning have blown out.
Flushing
If the air conditioning is still exhibiting intermittent cooling, or fails to work completely, the system may need to be flushed. Flushing chemicals can be bought from your local automotive supply store. Flushing your system is cheaper than replacing hoses and compressor components. If your compressor has failed, and a new one has been put in its place, it is still a good idea to flush the system, as a faulty compressor often shoots small flakes of metal through the entire system that tend to accumulate and clog the hoses. Also, if hoses in your system feel brittle, or are cracked, they will send small pieces of plastic along with the coolant. Replace these tubes and flush the system.
