AC System use freon. With the hood open, right in front of you there is a label which has some manufacturer codes on it. There you will find the type of Freon your car uses either R134A or R112. These you can buy at any autoparts store, or take your car to a AC specialist or the dealer and let them run a (sometimes Free) test and fill your Freon into your AC system.
The AC pipes are right infront of the washer fluid tank, it has a small glass which indicates the Freon.
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