I am installing a him into a patrol to control the heater box and have come across something that does not make sense. The him has a heat sink that would normally protrude into the hvac assembly. The heat sink seems to be for the fan driver but needs to dissipate the maximum heat when the fan is at its slowest, in fact gets quite hot at low fan speeds in free air to the point that the fan stops. If I am right this seems a very odd design.