You can hear furnace running but the blower never

do you mean the inside blower or the outside unit blower ... actually the problem might be a similar part in either case ... the blower motor has a capacitor mounted on it or near it ... it will be marked something like 160 uf at 200vac or similar . it will have wires attached or plugged into it .. the capacitor is what gives the blower motor a signal to tell it which way to start turning ... once the blower is running then the capacitor is no longer needed ... its only used to get the motor started ... if its bad then the motor will hum but wont turn .. if you manually spin the fan then the motor will take off in the direction you spun it (dont get hit ) .. a new capacitor is not expensive .. you need the numbers off the old "starting" capacitor or just take it with you to the parts place to match it up .. you may be able to order it from Ruud ... a HVAC repair person would likely be able to bring one with him for repair if you give him the numbers off the part or the model number of the furnace .. make sure the blower turns freely by hand (with power off) .. if not it may need bearings lubed .. ..