I am renting a 2014 VW Jetta 1.8L TSI I4 with the 6 speed Tiptronic AT and the performance of the A/C system is rather disappointing. I picked the car up in Las Vegas two hours ago with just over 9,000 miles on it and am currently in St. George, UT, grabbing a bite to eat. Ambient temps have ranged from 95F to 105F and the speed limit has been 75 mph most of the time. The car easily cruises at 75 mph at 2,200 rpm in 6th (AT) and gets 40 mpg doing so, but the A/C blows warm. If I slow to 70 mph (2,000 rpm), the A/C works decently, and it works flawlessly at 65 mph (1,800 rpm), both in 6th gear. I thought it might be vehicle or engine speed related, like a covert safety feature to get you to slow down, but when I drop it into 5th gear while at 75 mph, the rpm jump to 2,800 and the A/C works decently, about halfway between the 65 mph and 70 mph levels. I'm obviously not going to spend any money to fix it, but what's going on here?