I was also facing this issue. I went to lahore couple days back, there i needed to use AC but it wasnot giving optimal performance. Coming back to isb, i went to my dealer to check the AC performance, and guess what i found out ... my brand new swift AC only had 20grams of refrigerant gas in it
.... and the dealer stated we cannot cover this in warranty, so u'll have to pay 9rs. per gram for re-filling. This means i wud have to pay 4500 rs for total of 500grams of gas ... I argued with them, why there's no gas in ac, i purchased it from you zero meter and the thing went on blah blah till i got it resolved in warranty ... what these bloody sobs do is either the company doesnt fill the gas from behind to save their cost or the dealer extracts the gas from the car when arrives ....
Anyways, bottom line is, go to your dealer and tell them to check the AC properly for leakages as well as amount of gas there is in it.... in either case, if your car is in warranty, tell them to re-fill it..... Mine's AC is performing classy now after refilling of gas.
Regards