Some time ago I remember looking at that coil and also thinking it was a heating coil. But I'm pretty sure it is only the resistor that allows for motor to go to a lower speed (in conjunction with the 2-speed switch). On DC motors they switch in resistors to change the fan speed.
Adding a little heater to the airstream would have helped.
Toolmanmike's first comment that factory system just blows air is correct.
