The fan speed is controlled by the resistor. If it only works on HIGH speed the resistor is bad.
(Money saving tip) Next time you need wiper arms order them without the wiper blades...you would't believe how much you pay for wiper blades when...
That casting # is for a FW3500 top plate. You need a RK-63501 rebuild kit if it is left hand pull.
SCR - selective catalytic reduction