99 jetta overheating

99 jetta started overheating a week ago. When the car is running the upper radiator hose is hot and the lower one is cool so I am assuming the thermostat is opening. When I jumpered the fan thermo switch the fans started to come on and I thought I had the problem. But when I took it for a ride it started to over heat again at higher speeds and would cool down at idle (with the engine running) even with the fans running at high speed. Thought maybe air had gotten into the system and tried to bleed it. Checked the coolant sensor for the proper resistance while hot and cold and it was correct. Coolant levels are also okay. Water pump doesn't seem to be faulty but not exactly sure how to check it. Any help would be greatly appreciated. Also neither the heater or AC will now work.