I'm not familiar with the T2000 but on most trucks after checking to make sure there is not a blown fuse or breaker, remove the control panel in the bunk and then with a test light check for fire on both the rheostat/temperature control and the fan speed switch if you have fire on both sides there find the fan motor (probably under the bunk) and check for fire. If any of these have fire going in but none coming out then there's your problem, or if you have fire going into the fan motor and it doesn't turn then you need a new motor.