One of the main purposes of automotive air conditioning is to make you feel as comfortable in your car as you would feel in your bedroom. However, the fact is that your car's air conditioning is quite different from the air conditioning present in your bedroom. At the same time, it is more prone to problems and difficulties. There is no need, however, to take it to the service center each time some such problem occurs. You can look into many of these things yourself, or solve the problem by replacing some parts. Given below is a basic troubleshooting guide.
Problem # 1 - Blower Fan Problems
When a blower fan problem occurs with your air conditioning, the most significant thing that will happen is that cold air will not circulate within the vehicle. You will have to check out the functioning of the blower fan. This is done as follows. Put the AC of your car on. Then start the blower fan and put it at maximum. If this blower fan is fine, you should hear it blowing clear and loud. If you cannot hear it, or if the sound is muted, then the blower fan needs repair or replacement.
Problem # 2 - Fuse Problems
If there is no problem with your blower fan, then most probably the problem lies in the fuse that connects to the motor of the blower fan. You will find the fuse under the dash area. When this fuse is located, you can easily find out whether it is working properly or not. If it is blown, then you will have to replace it with a new one. When replacing, take care and see that the old fuse is compatible with the one you are purchasing. Remove the old, blown one as instructed and then replace it with a similarly rated fuse. However, if the new fuse blows again, then you either have a faulty blower motor or there is a short somewhere in the circuit. In that case, you will need professional help.
Problem # 3 - Compressor Problems
The compressor is often called the heart of an air conditioning system, and any problem with it should be rectified without delay. One of the basic problems can be with its magnetic clutch. If there is no cooling in the vehicle, this could be a problem. If you are sure that it is not the fuse that's faulty, and if the clutch is not getting engaged with the AC, then there's a fault there. You will have to replace the clutch. Additionally or otherwise, there could be leakage of fuel around the shaft seal of the compressor. If so, you are wasting your precious fuel and also not getting any cooling. Replace the seal.
Problem # 4 - Fuel Problems
Older automotive air conditioning systems use the R-12 systems which need mineral oils, while the newer systems use the R-134A systems which need PAG oils. Using mineral oil in a R-134A system can create a fault with the cooling. So, you need to ensure that you use the right kind of oil. Leakage problems are also quite common. If leakage occurs around the shaft seal, you need to replace it. Newer systems have better-fitting seals, so the leakage problems are reduced anyway. Another place where leakage of fuel is common is around the hose. The hose might develop pores, from which the leakage occurs. Regularly check the hose. If you find any stains there, then there is a leakage. Replace it to get better efficiency and save on your fuel.
Problem # 5 - Pressure Problems
All automotive air conditioning systems have two ducts - the low and the high pressure ducts. Erroneous pressures in these ducts can cause a host of problems. If the low pressure duct is subjected to high pressure, then possible faults are overcharge of the refrigerant (Freon) or air in the system. However, if the high pressure end is getting low pressure, then faults could be a low refrigerant charge, a stuck expansion valve, plugged orifice tube, or some other kind of restriction on the high side. You will have to check the manual to solve these problems.
Problem # 6 - Miscellaneous
Sometimes, the air does not circulate inside the vehicle because your controls are not working properly. Check all the control buttons. They should move freely and well. If not, perhaps the buttons need replacement. Also look into the circulation button provided with the car air conditioning system. Sometimes, this button is accidentally switched off. Problems with intermittent cooling, where you get warm air in between the cooling, are probably due to freezing up of the systems. This can be cured by purging the entire system of blocked air and moisture and then reusing it. For this, you will need a vacuum pump.
For every problem, there is a specific solution, but what's more important is that you must diagnose the problem well. There is a lot of information in your manual and several troubleshooting guides online to help you out. Look into them before calling up the service people.