Last three road trips i've made the AC fan shuts way down after about 2 1/2 hours of driving (ambient temp outside has remained the same- hot). Even when I punch MAX it doesn't change much- you can hear lots of fan noise, but not much air coming out any of the AC vents- body, dash, floor. (MAX setting when I first start the car is fine, cools down quickly, lots of air blowing through the vents). For the first couple of hours everything is fine- no changes made to any of the settings i-drive or otherwise. Just a diminution of air coming out. Car is a 2008 4.8, about 16,000 miles. Anybody experience anything similar? Thanks.