Ok.
Welcome

Next step...go to the appropriate section of this forum...that would be problems and annoyances.

Next step...click on the search button...that'll get you quite a ways here without being treated like a second class citizen.

Next step...in the keywords box type "blower motor resistor" and click on search.

Next step...read the directions on how to replace said resistor.

Next step...enjoy having all 4 speeds on your HVAC controls

Welcome to XOC