I have a 1998 Ford Explorer XLT, 5.0L V8 RWD. When the truck is parked and the engine is cool, I reach over and turn on "Max A/C". Cold air comes out and all is well. During the next few minutes, the A/C starts to get warmer and warmer then hot. The same happens when I put the vehicle into gear and press the accelerator... it gets hot and does not go back to cold. The system is charged correctly, and it sounds like the blend door is moving when I switch between Hot & Cold. At the same time, when I try to use normal A/C, it is hot all the time. My heat works fine, but it's almost as if I can't get the Hot/Cool switch to work, even though there's a click behind the glove box where the blend door is when I switch it. Any ideas as to what's going on here? I've looked high and low on the internet and can't find anything related to my problem.

Perform the tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-9.html#post1864159

While the manifold gauge set is attached, check the cut-in (50 psi) and cut-out (22 psi) pressures for the Clutch Cycling Switch. If you perform these tests, you will solve the problem.

System Specifications:

Low Side Gauge Pressure: 22 to 50 psi
High Side Gauge Pressure: 160 to 250 psi

System Refrigerant Capacity: 1.88 lbs.

System Refrigerant Oil Capacity: 9 ounces

The clicking noise is the blend door motor gears. Do you have dual ac control in front? Passanger and driver? If so there are two blend door motors that control each side... my gues is no... so if the actuator is clicking... replace it... the gears inside are stripped

Thanks to everyone for your help. It ended up being a broken tab at the top of the blend door. I was able to cut a door into the blend box behind the glove box and manually "move" the blend door itself to the position/temperature that I wanted. I then closed the make-shift door and sealed it with duct tape. It was a pain to switch back and forth but I rarely had to do so. I no longer have the truck though as I traded it for a Pontiac Firebird.