I too have a quadrunner 500 that is overheating. I have checked the water level and it is full. the fan is not coming on. I checked the voltage at the fuse and i do not have 12 volts there when the over temp light comes on. Where is this hose going to the fan or sensor? that may be stopped up. Does anyone have a wiring diagram of this system or can you tell me where i can get one? i have someone that wants to buy it, but i want to get this fixed first. Also can anyone tell me what a 1998 500 Quadrunner is worth? Mechanically it is great with some cosmetic problems. [img]i/expressions/face-icon-small-disgusted.gif[/img]