Originally Posted by SumAccordGuy94

sounds most like an issue with the motor RESISTOR, not Transistor (a solid-state electronic device that is used to control the flow of electricity in electronic equipment and consists of a small block of a semiconductor (as germanium) with at least three electrodes)

The resistor controls the speed of the motor by limiting the current, its pretty normal for the low speeds to fail over time. It is also possible that it came disconnected.

If the motor was bad it wouldnt work at all... or fill the car up with smoke.