Why would ac quit after driving a while pulling a trailer

Hello, It is most likely that your engine or transmission is becoming too hot. When the engine warms to a certain point, the A/C is shut off to reduce load. This is why it will work when driving with no added load. If you have oversize tires, are towing at speeds over 55-65, are towing in overdrive, or are towing in 4hi, this is nearly certain to happen. The 4.0l is a great engine, much better than the older 3.3l, but I wouldn't put anything larger than a 2000-2500lbs behind one.