I have a 5 year old Carrier furnace. Two weeks ago I had a repairman out because the furnace was not blowing warm air and he replaced a limit control to the tune of $215. Now, two weeks later, the same thing is happening. The repairmen replaced the 3/4 hp blower motor and still the furnace is not working properly. They left to go back to the shop for yet another part - (not absolutely sure what they called it - either a switch or an inducer). It is supposed to regulate or kick on the blower motor. What part would that be and how is it different from the limit control that was replaced 2 weeks ago?

Thank you.