It is that time of year when you try your AC for the first time and no cold air. Don’t panic; listen for a clicking which will be the AC compressor clutch. If it is clicking on and off you are probably a little low on Freon. If it not engaging you are probably still low on Freon. More than likely you will have a 134A in your system, if your service valves have threads and are small take it to a shop and have it retrofitted. Purchase a kit from the parts store, keep the gauge and hose and next time you will only need Freon.Be sure to clean the service valve before attaching the hose even a grain of sand can damage a compressor. The hose slips unto the valve and locks in place with a click. Attach the hose to the low pressure side this will be the larger of the two hoses. Holding the can hose end down tighten the valve to pierce the can and then back it off to start filling, shaking the can will speed up the process and assure getting all the contents out. Continue filing until the pressure is in the green, if the compressor was not running you may see the gauge jump and hear the compressor kick on and off, this is normal. When the gauge is in the green shut off the can and remove the hose. You should now have cold air if not it is shop time unless you have some AC experience and a set of gauges. When servicing the AC it is a good idea to also check the belt for condition and the condenser for any blockage between the radiator and the condenser, easy to clean at the local car wash with a pressure wand. Also check the area to the front of the windshield this grate area should be free of debris.Have seen numerous vehicles with crud on the evaporator blocking air passage this usually have a musty odor, some vehicles can be cleaned by simply removing the heater blower motor other take drastic disassembly. If you have an odor and good air flow there are several products on the market that do a fair job of removing the odor. I am usually not cautious enough when performing repairs but I always wear gloves and a face shield when working on AC, Freon is really cold and it hurts when coming in contact with skin this I can tell you from experience.