Do you have a battery charger? If not you can use two pieces of wire and the battery in the wheeler. Unhook the plug to the fan and hook the red wire to positive and the brown wire to ground, if the fan doesn't work, you know its the fan , if it does then its the temp sensor or thermostat, yes it has a thermostat. You can remove the thermostat and put it in a pan of water and heat it on the stove with a thermometer in the pan , should open at 180.

 

where do i unplug it at.... on the top of the radiatior where the sensor is... there are only 2 red and white wires... and.. yes i do have a charger... but the only place i see the brown wire is at the circut board... or its down by the bottom of the fan... its wierd the red wire either splits into 2 or somthing im not sure...