I have a 99 Jetta VR6 with a cooling problem. The first sign of the overheating was on a city road under low RPM situation. I was low on coolant. I filled it up to the top and was still overheating. I was not losing coolant anymore though. After parking the next night and the engine was still hot I realized the fans were not on. I checked them while the engine was running and they still did not run. I bypassed the thermo switch and the fans came on like they should both high and low speeds. So I thought my thermo switch was the problem but since I couldnt get a thermo switch that day I ran a toggle switch into my dash and I can manually turn the fans on. I figured that was the fix...wrong. I still overheat. That night I drove the car home from the garage I fixed it in and ran the fans on high all the way home. About halfway home I overheated again. Now I am stuck, the water pump is working, the thermostat is not stuck open or closed because the return hose from the radiator is hot meaning that at the least the coolant is moving through the radiator. Where should I go from here. Any help would be much appreciated.